diff -urN drivers.old//staging/zcache/Makefile drivers//staging/zcache/Makefile --- drivers.old//staging/zcache/Makefile 2011-07-22 04:17:23.000000000 +0200 +++ drivers//staging/zcache/Makefile 2011-07-25 12:02:14.028241844 +0200 @@ -1,3 +1,3 @@ -zcache-y := tmem.o +zcache-y := zcache_drv.o tmem.o obj-$(CONFIG_ZCACHE) += zcache.o diff -urN drivers.old//staging/zcache/zcache.c drivers//staging/zcache/zcache.c --- drivers.old//staging/zcache/zcache.c 2011-07-22 04:17:23.000000000 +0200 +++ drivers//staging/zcache/zcache.c 1970-01-01 01:00:00.000000000 +0100 @@ -1,1661 +0,0 @@ -/* - * zcache.c - * - * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp. - * Copyright (c) 2010,2011, Nitin Gupta - * - * Zcache provides an in-kernel "host implementation" for transcendent memory - * and, thus indirectly, for cleancache and frontswap. Zcache includes two - * page-accessible memory [1] interfaces, both utilizing lzo1x compression: - * 1) "compression buddies" ("zbud") is used for ephemeral pages - * 2) xvmalloc is used for persistent pages. - * Xvmalloc (based on the TLSF allocator) has very low fragmentation - * so maximizes space efficiency, while zbud allows pairs (and potentially, - * in the future, more than a pair of) compressed pages to be closely linked - * so that reclaiming can be done via the kernel's physical-page-oriented - * "shrinker" interface. - * - * [1] For a definition of page-accessible memory (aka PAM), see: - * http://marc.info/?l=linux-mm&m=127811271605009 - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include "tmem.h" - -#include "../zram/xvmalloc.h" /* if built in drivers/staging */ - -#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP)) -#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP" -#endif -#ifdef CONFIG_CLEANCACHE -#include -#endif -#ifdef CONFIG_FRONTSWAP -#include -#endif - -#if 0 -/* this is more aggressive but may cause other problems? */ -#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN) -#else -#define ZCACHE_GFP_MASK \ - (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC) -#endif - -/********** - * Compression buddies ("zbud") provides for packing two (or, possibly - * in the future, more) compressed ephemeral pages into a single "raw" - * (physical) page and tracking them with data structures so that - * the raw pages can be easily reclaimed. - * - * A zbud page ("zbpg") is an aligned page containing a list_head, - * a lock, and two "zbud headers". The remainder of the physical - * page is divided up into aligned 64-byte "chunks" which contain - * the compressed data for zero, one, or two zbuds. Each zbpg - * resides on: (1) an "unused list" if it has no zbuds; (2) a - * "buddied" list if it is fully populated with two zbuds; or - * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks - * the one unbuddied zbud uses. The data inside a zbpg cannot be - * read or written unless the zbpg's lock is held. - */ - -#define ZBH_SENTINEL 0x43214321 -#define ZBPG_SENTINEL 0xdeadbeef - -#define ZBUD_MAX_BUDS 2 - -struct zbud_hdr { - uint32_t pool_id; - struct tmem_oid oid; - uint32_t index; - uint16_t size; /* compressed size in bytes, zero means unused */ - DECL_SENTINEL -}; - -struct zbud_page { - struct list_head bud_list; - spinlock_t lock; - struct zbud_hdr buddy[ZBUD_MAX_BUDS]; - DECL_SENTINEL - /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */ -}; - -#define CHUNK_SHIFT 6 -#define CHUNK_SIZE (1 << CHUNK_SHIFT) -#define CHUNK_MASK (~(CHUNK_SIZE-1)) -#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \ - CHUNK_MASK) >> CHUNK_SHIFT) -#define MAX_CHUNK (NCHUNKS-1) - -static struct { - struct list_head list; - unsigned count; -} zbud_unbuddied[NCHUNKS]; -/* list N contains pages with N chunks USED and NCHUNKS-N unused */ -/* element 0 is never used but optimizing that isn't worth it */ -static unsigned long zbud_cumul_chunk_counts[NCHUNKS]; - -struct list_head zbud_buddied_list; -static unsigned long zcache_zbud_buddied_count; - -/* protects the buddied list and all unbuddied lists */ -static DEFINE_SPINLOCK(zbud_budlists_spinlock); - -static LIST_HEAD(zbpg_unused_list); -static unsigned long zcache_zbpg_unused_list_count; - -/* protects the unused page list */ -static DEFINE_SPINLOCK(zbpg_unused_list_spinlock); - -static atomic_t zcache_zbud_curr_raw_pages; -static atomic_t zcache_zbud_curr_zpages; -static unsigned long zcache_zbud_curr_zbytes; -static unsigned long zcache_zbud_cumul_zpages; -static unsigned long zcache_zbud_cumul_zbytes; -static unsigned long zcache_compress_poor; - -/* forward references */ -static void *zcache_get_free_page(void); -static void zcache_free_page(void *p); - -/* - * zbud helper functions - */ - -static inline unsigned zbud_max_buddy_size(void) -{ - return MAX_CHUNK << CHUNK_SHIFT; -} - -static inline unsigned zbud_size_to_chunks(unsigned size) -{ - BUG_ON(size == 0 || size > zbud_max_buddy_size()); - return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT; -} - -static inline int zbud_budnum(struct zbud_hdr *zh) -{ - unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1); - struct zbud_page *zbpg = NULL; - unsigned budnum = -1U; - int i; - - for (i = 0; i < ZBUD_MAX_BUDS; i++) - if (offset == offsetof(typeof(*zbpg), buddy[i])) { - budnum = i; - break; - } - BUG_ON(budnum == -1U); - return budnum; -} - -static char *zbud_data(struct zbud_hdr *zh, unsigned size) -{ - struct zbud_page *zbpg; - char *p; - unsigned budnum; - - ASSERT_SENTINEL(zh, ZBH); - budnum = zbud_budnum(zh); - BUG_ON(size == 0 || size > zbud_max_buddy_size()); - zbpg = container_of(zh, struct zbud_page, buddy[budnum]); - ASSERT_SPINLOCK(&zbpg->lock); - p = (char *)zbpg; - if (budnum == 0) - p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) & - CHUNK_MASK); - else if (budnum == 1) - p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK); - return p; -} - -/* - * zbud raw page management - */ - -static struct zbud_page *zbud_alloc_raw_page(void) -{ - struct zbud_page *zbpg = NULL; - struct zbud_hdr *zh0, *zh1; - bool recycled = 0; - - /* if any pages on the zbpg list, use one */ - spin_lock(&zbpg_unused_list_spinlock); - if (!list_empty(&zbpg_unused_list)) { - zbpg = list_first_entry(&zbpg_unused_list, - struct zbud_page, bud_list); - list_del_init(&zbpg->bud_list); - zcache_zbpg_unused_list_count--; - recycled = 1; - } - spin_unlock(&zbpg_unused_list_spinlock); - if (zbpg == NULL) - /* none on zbpg list, try to get a kernel page */ - zbpg = zcache_get_free_page(); - if (likely(zbpg != NULL)) { - INIT_LIST_HEAD(&zbpg->bud_list); - zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1]; - spin_lock_init(&zbpg->lock); - if (recycled) { - ASSERT_INVERTED_SENTINEL(zbpg, ZBPG); - SET_SENTINEL(zbpg, ZBPG); - BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid)); - BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid)); - } else { - atomic_inc(&zcache_zbud_curr_raw_pages); - INIT_LIST_HEAD(&zbpg->bud_list); - SET_SENTINEL(zbpg, ZBPG); - zh0->size = 0; zh1->size = 0; - tmem_oid_set_invalid(&zh0->oid); - tmem_oid_set_invalid(&zh1->oid); - } - } - return zbpg; -} - -static void zbud_free_raw_page(struct zbud_page *zbpg) -{ - struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1]; - - ASSERT_SENTINEL(zbpg, ZBPG); - BUG_ON(!list_empty(&zbpg->bud_list)); - ASSERT_SPINLOCK(&zbpg->lock); - BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid)); - BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid)); - INVERT_SENTINEL(zbpg, ZBPG); - spin_unlock(&zbpg->lock); - spin_lock(&zbpg_unused_list_spinlock); - list_add(&zbpg->bud_list, &zbpg_unused_list); - zcache_zbpg_unused_list_count++; - spin_unlock(&zbpg_unused_list_spinlock); -} - -/* - * core zbud handling routines - */ - -static unsigned zbud_free(struct zbud_hdr *zh) -{ - unsigned size; - - ASSERT_SENTINEL(zh, ZBH); - BUG_ON(!tmem_oid_valid(&zh->oid)); - size = zh->size; - BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size()); - zh->size = 0; - tmem_oid_set_invalid(&zh->oid); - INVERT_SENTINEL(zh, ZBH); - zcache_zbud_curr_zbytes -= size; - atomic_dec(&zcache_zbud_curr_zpages); - return size; -} - -static void zbud_free_and_delist(struct zbud_hdr *zh) -{ - unsigned chunks; - struct zbud_hdr *zh_other; - unsigned budnum = zbud_budnum(zh), size; - struct zbud_page *zbpg = - container_of(zh, struct zbud_page, buddy[budnum]); - - spin_lock(&zbpg->lock); - if (list_empty(&zbpg->bud_list)) { - /* ignore zombie page... see zbud_evict_pages() */ - spin_unlock(&zbpg->lock); - return; - } - size = zbud_free(zh); - ASSERT_SPINLOCK(&zbpg->lock); - zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0]; - if (zh_other->size == 0) { /* was unbuddied: unlist and free */ - chunks = zbud_size_to_chunks(size) ; - spin_lock(&zbud_budlists_spinlock); - BUG_ON(list_empty(&zbud_unbuddied[chunks].list)); - list_del_init(&zbpg->bud_list); - zbud_unbuddied[chunks].count--; - spin_unlock(&zbud_budlists_spinlock); - zbud_free_raw_page(zbpg); - } else { /* was buddied: move remaining buddy to unbuddied list */ - chunks = zbud_size_to_chunks(zh_other->size) ; - spin_lock(&zbud_budlists_spinlock); - list_del_init(&zbpg->bud_list); - zcache_zbud_buddied_count--; - list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list); - zbud_unbuddied[chunks].count++; - spin_unlock(&zbud_budlists_spinlock); - spin_unlock(&zbpg->lock); - } -} - -static struct zbud_hdr *zbud_create(uint32_t pool_id, struct tmem_oid *oid, - uint32_t index, struct page *page, - void *cdata, unsigned size) -{ - struct zbud_hdr *zh0, *zh1, *zh = NULL; - struct zbud_page *zbpg = NULL, *ztmp; - unsigned nchunks; - char *to; - int i, found_good_buddy = 0; - - nchunks = zbud_size_to_chunks(size) ; - for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) { - spin_lock(&zbud_budlists_spinlock); - if (!list_empty(&zbud_unbuddied[i].list)) { - list_for_each_entry_safe(zbpg, ztmp, - &zbud_unbuddied[i].list, bud_list) { - if (spin_trylock(&zbpg->lock)) { - found_good_buddy = i; - goto found_unbuddied; - } - } - } - spin_unlock(&zbud_budlists_spinlock); - } - /* didn't find a good buddy, try allocating a new page */ - zbpg = zbud_alloc_raw_page(); - if (unlikely(zbpg == NULL)) - goto out; - /* ok, have a page, now compress the data before taking locks */ - spin_lock(&zbpg->lock); - spin_lock(&zbud_budlists_spinlock); - list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list); - zbud_unbuddied[nchunks].count++; - zh = &zbpg->buddy[0]; - goto init_zh; - -found_unbuddied: - ASSERT_SPINLOCK(&zbpg->lock); - zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1]; - BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0))); - if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */ - ASSERT_SENTINEL(zh0, ZBH); - zh = zh1; - } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */ - ASSERT_SENTINEL(zh1, ZBH); - zh = zh0; - } else - BUG(); - list_del_init(&zbpg->bud_list); - zbud_unbuddied[found_good_buddy].count--; - list_add_tail(&zbpg->bud_list, &zbud_buddied_list); - zcache_zbud_buddied_count++; - -init_zh: - SET_SENTINEL(zh, ZBH); - zh->size = size; - zh->index = index; - zh->oid = *oid; - zh->pool_id = pool_id; - /* can wait to copy the data until the list locks are dropped */ - spin_unlock(&zbud_budlists_spinlock); - - to = zbud_data(zh, size); - memcpy(to, cdata, size); - spin_unlock(&zbpg->lock); - zbud_cumul_chunk_counts[nchunks]++; - atomic_inc(&zcache_zbud_curr_zpages); - zcache_zbud_cumul_zpages++; - zcache_zbud_curr_zbytes += size; - zcache_zbud_cumul_zbytes += size; -out: - return zh; -} - -static int zbud_decompress(struct page *page, struct zbud_hdr *zh) -{ - struct zbud_page *zbpg; - unsigned budnum = zbud_budnum(zh); - size_t out_len = PAGE_SIZE; - char *to_va, *from_va; - unsigned size; - int ret = 0; - - zbpg = container_of(zh, struct zbud_page, buddy[budnum]); - spin_lock(&zbpg->lock); - if (list_empty(&zbpg->bud_list)) { - /* ignore zombie page... see zbud_evict_pages() */ - ret = -EINVAL; - goto out; - } - ASSERT_SENTINEL(zh, ZBH); - BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size()); - to_va = kmap_atomic(page, KM_USER0); - size = zh->size; - from_va = zbud_data(zh, size); - ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len); - BUG_ON(ret != LZO_E_OK); - BUG_ON(out_len != PAGE_SIZE); - kunmap_atomic(to_va, KM_USER0); -out: - spin_unlock(&zbpg->lock); - return ret; -} - -/* - * The following routines handle shrinking of ephemeral pages by evicting - * pages "least valuable" first. - */ - -static unsigned long zcache_evicted_raw_pages; -static unsigned long zcache_evicted_buddied_pages; -static unsigned long zcache_evicted_unbuddied_pages; - -static struct tmem_pool *zcache_get_pool_by_id(uint32_t poolid); -static void zcache_put_pool(struct tmem_pool *pool); - -/* - * Flush and free all zbuds in a zbpg, then free the pageframe - */ -static void zbud_evict_zbpg(struct zbud_page *zbpg) -{ - struct zbud_hdr *zh; - int i, j; - uint32_t pool_id[ZBUD_MAX_BUDS], index[ZBUD_MAX_BUDS]; - struct tmem_oid oid[ZBUD_MAX_BUDS]; - struct tmem_pool *pool; - - ASSERT_SPINLOCK(&zbpg->lock); - BUG_ON(!list_empty(&zbpg->bud_list)); - for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) { - zh = &zbpg->buddy[i]; - if (zh->size) { - pool_id[j] = zh->pool_id; - oid[j] = zh->oid; - index[j] = zh->index; - j++; - zbud_free(zh); - } - } - spin_unlock(&zbpg->lock); - for (i = 0; i < j; i++) { - pool = zcache_get_pool_by_id(pool_id[i]); - if (pool != NULL) { - tmem_flush_page(pool, &oid[i], index[i]); - zcache_put_pool(pool); - } - } - ASSERT_SENTINEL(zbpg, ZBPG); - spin_lock(&zbpg->lock); - zbud_free_raw_page(zbpg); -} - -/* - * Free nr pages. This code is funky because we want to hold the locks - * protecting various lists for as short a time as possible, and in some - * circumstances the list may change asynchronously when the list lock is - * not held. In some cases we also trylock not only to avoid waiting on a - * page in use by another cpu, but also to avoid potential deadlock due to - * lock inversion. - */ -static void zbud_evict_pages(int nr) -{ - struct zbud_page *zbpg; - int i; - - /* first try freeing any pages on unused list */ -retry_unused_list: - spin_lock_bh(&zbpg_unused_list_spinlock); - if (!list_empty(&zbpg_unused_list)) { - /* can't walk list here, since it may change when unlocked */ - zbpg = list_first_entry(&zbpg_unused_list, - struct zbud_page, bud_list); - list_del_init(&zbpg->bud_list); - zcache_zbpg_unused_list_count--; - atomic_dec(&zcache_zbud_curr_raw_pages); - spin_unlock_bh(&zbpg_unused_list_spinlock); - zcache_free_page(zbpg); - zcache_evicted_raw_pages++; - if (--nr <= 0) - goto out; - goto retry_unused_list; - } - spin_unlock_bh(&zbpg_unused_list_spinlock); - - /* now try freeing unbuddied pages, starting with least space avail */ - for (i = 0; i < MAX_CHUNK; i++) { -retry_unbud_list_i: - spin_lock_bh(&zbud_budlists_spinlock); - if (list_empty(&zbud_unbuddied[i].list)) { - spin_unlock_bh(&zbud_budlists_spinlock); - continue; - } - list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) { - if (unlikely(!spin_trylock(&zbpg->lock))) - continue; - list_del_init(&zbpg->bud_list); - zbud_unbuddied[i].count--; - spin_unlock(&zbud_budlists_spinlock); - zcache_evicted_unbuddied_pages++; - /* want budlists unlocked when doing zbpg eviction */ - zbud_evict_zbpg(zbpg); - local_bh_enable(); - if (--nr <= 0) - goto out; - goto retry_unbud_list_i; - } - spin_unlock_bh(&zbud_budlists_spinlock); - } - - /* as a last resort, free buddied pages */ -retry_bud_list: - spin_lock_bh(&zbud_budlists_spinlock); - if (list_empty(&zbud_buddied_list)) { - spin_unlock_bh(&zbud_budlists_spinlock); - goto out; - } - list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) { - if (unlikely(!spin_trylock(&zbpg->lock))) - continue; - list_del_init(&zbpg->bud_list); - zcache_zbud_buddied_count--; - spin_unlock(&zbud_budlists_spinlock); - zcache_evicted_buddied_pages++; - /* want budlists unlocked when doing zbpg eviction */ - zbud_evict_zbpg(zbpg); - local_bh_enable(); - if (--nr <= 0) - goto out; - goto retry_bud_list; - } - spin_unlock_bh(&zbud_budlists_spinlock); -out: - return; -} - -static void zbud_init(void) -{ - int i; - - INIT_LIST_HEAD(&zbud_buddied_list); - zcache_zbud_buddied_count = 0; - for (i = 0; i < NCHUNKS; i++) { - INIT_LIST_HEAD(&zbud_unbuddied[i].list); - zbud_unbuddied[i].count = 0; - } -} - -#ifdef CONFIG_SYSFS -/* - * These sysfs routines show a nice distribution of how many zbpg's are - * currently (and have ever been placed) in each unbuddied list. It's fun - * to watch but can probably go away before final merge. - */ -static int zbud_show_unbuddied_list_counts(char *buf) -{ - int i; - char *p = buf; - - for (i = 0; i < NCHUNKS - 1; i++) - p += sprintf(p, "%u ", zbud_unbuddied[i].count); - p += sprintf(p, "%d\n", zbud_unbuddied[i].count); - return p - buf; -} - -static int zbud_show_cumul_chunk_counts(char *buf) -{ - unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0; - unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0; - unsigned long total_chunks_lte_42 = 0; - char *p = buf; - - for (i = 0; i < NCHUNKS; i++) { - p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]); - chunks += zbud_cumul_chunk_counts[i]; - total_chunks += zbud_cumul_chunk_counts[i]; - sum_total_chunks += i * zbud_cumul_chunk_counts[i]; - if (i == 21) - total_chunks_lte_21 = total_chunks; - if (i == 32) - total_chunks_lte_32 = total_chunks; - if (i == 42) - total_chunks_lte_42 = total_chunks; - } - p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n", - total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42, - chunks == 0 ? 0 : sum_total_chunks / chunks); - return p - buf; -} -#endif - -/********** - * This "zv" PAM implementation combines the TLSF-based xvMalloc - * with lzo1x compression to maximize the amount of data that can - * be packed into a physical page. - * - * Zv represents a PAM page with the index and object (plus a "size" value - * necessary for decompression) immediately preceding the compressed data. - */ - -#define ZVH_SENTINEL 0x43214321 - -struct zv_hdr { - uint32_t pool_id; - struct tmem_oid oid; - uint32_t index; - DECL_SENTINEL -}; - -static const int zv_max_page_size = (PAGE_SIZE / 8) * 7; - -static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id, - struct tmem_oid *oid, uint32_t index, - void *cdata, unsigned clen) -{ - struct page *page; - struct zv_hdr *zv = NULL; - uint32_t offset; - int ret; - - BUG_ON(!irqs_disabled()); - ret = xv_malloc(xvpool, clen + sizeof(struct zv_hdr), - &page, &offset, ZCACHE_GFP_MASK); - if (unlikely(ret)) - goto out; - zv = kmap_atomic(page, KM_USER0) + offset; - zv->index = index; - zv->oid = *oid; - zv->pool_id = pool_id; - SET_SENTINEL(zv, ZVH); - memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen); - kunmap_atomic(zv, KM_USER0); -out: - return zv; -} - -static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv) -{ - unsigned long flags; - struct page *page; - uint32_t offset; - uint16_t size; - - ASSERT_SENTINEL(zv, ZVH); - size = xv_get_object_size(zv) - sizeof(*zv); - BUG_ON(size == 0 || size > zv_max_page_size); - INVERT_SENTINEL(zv, ZVH); - page = virt_to_page(zv); - offset = (unsigned long)zv & ~PAGE_MASK; - local_irq_save(flags); - xv_free(xvpool, page, offset); - local_irq_restore(flags); -} - -static void zv_decompress(struct page *page, struct zv_hdr *zv) -{ - size_t clen = PAGE_SIZE; - char *to_va; - unsigned size; - int ret; - - ASSERT_SENTINEL(zv, ZVH); - size = xv_get_object_size(zv) - sizeof(*zv); - BUG_ON(size == 0 || size > zv_max_page_size); - to_va = kmap_atomic(page, KM_USER0); - ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv), - size, to_va, &clen); - kunmap_atomic(to_va, KM_USER0); - BUG_ON(ret != LZO_E_OK); - BUG_ON(clen != PAGE_SIZE); -} - -/* - * zcache core code starts here - */ - -/* useful stats not collected by cleancache or frontswap */ -static unsigned long zcache_flush_total; -static unsigned long zcache_flush_found; -static unsigned long zcache_flobj_total; -static unsigned long zcache_flobj_found; -static unsigned long zcache_failed_eph_puts; -static unsigned long zcache_failed_pers_puts; - -#define MAX_POOLS_PER_CLIENT 16 - -static struct { - struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT]; - struct xv_pool *xvpool; -} zcache_client; - -/* - * Tmem operations assume the poolid implies the invoking client. - * Zcache only has one client (the kernel itself), so translate - * the poolid into the tmem_pool allocated for it. A KVM version - * of zcache would have one client per guest and each client might - * have a poolid==N. - */ -static struct tmem_pool *zcache_get_pool_by_id(uint32_t poolid) -{ - struct tmem_pool *pool = NULL; - - if (poolid >= 0) { - pool = zcache_client.tmem_pools[poolid]; - if (pool != NULL) - atomic_inc(&pool->refcount); - } - return pool; -} - -static void zcache_put_pool(struct tmem_pool *pool) -{ - if (pool != NULL) - atomic_dec(&pool->refcount); -} - -/* counters for debugging */ -static unsigned long zcache_failed_get_free_pages; -static unsigned long zcache_failed_alloc; -static unsigned long zcache_put_to_flush; -static unsigned long zcache_aborted_preload; -static unsigned long zcache_aborted_shrink; - -/* - * Ensure that memory allocation requests in zcache don't result - * in direct reclaim requests via the shrinker, which would cause - * an infinite loop. Maybe a GFP flag would be better? - */ -static DEFINE_SPINLOCK(zcache_direct_reclaim_lock); - -/* - * for now, used named slabs so can easily track usage; later can - * either just use kmalloc, or perhaps add a slab-like allocator - * to more carefully manage total memory utilization - */ -static struct kmem_cache *zcache_objnode_cache; -static struct kmem_cache *zcache_obj_cache; -static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0); -static unsigned long zcache_curr_obj_count_max; -static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0); -static unsigned long zcache_curr_objnode_count_max; - -/* - * to avoid memory allocation recursion (e.g. due to direct reclaim), we - * preload all necessary data structures so the hostops callbacks never - * actually do a malloc - */ -struct zcache_preload { - void *page; - struct tmem_obj *obj; - int nr; - struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH]; -}; -static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, }; - -static int zcache_do_preload(struct tmem_pool *pool) -{ - struct zcache_preload *kp; - struct tmem_objnode *objnode; - struct tmem_obj *obj; - void *page; - int ret = -ENOMEM; - - if (unlikely(zcache_objnode_cache == NULL)) - goto out; - if (unlikely(zcache_obj_cache == NULL)) - goto out; - if (!spin_trylock(&zcache_direct_reclaim_lock)) { - zcache_aborted_preload++; - goto out; - } - preempt_disable(); - kp = &__get_cpu_var(zcache_preloads); - while (kp->nr < ARRAY_SIZE(kp->objnodes)) { - preempt_enable_no_resched(); - objnode = kmem_cache_alloc(zcache_objnode_cache, - ZCACHE_GFP_MASK); - if (unlikely(objnode == NULL)) { - zcache_failed_alloc++; - goto unlock_out; - } - preempt_disable(); - kp = &__get_cpu_var(zcache_preloads); - if (kp->nr < ARRAY_SIZE(kp->objnodes)) - kp->objnodes[kp->nr++] = objnode; - else - kmem_cache_free(zcache_objnode_cache, objnode); - } - preempt_enable_no_resched(); - obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK); - if (unlikely(obj == NULL)) { - zcache_failed_alloc++; - goto unlock_out; - } - page = (void *)__get_free_page(ZCACHE_GFP_MASK); - if (unlikely(page == NULL)) { - zcache_failed_get_free_pages++; - kmem_cache_free(zcache_obj_cache, obj); - goto unlock_out; - } - preempt_disable(); - kp = &__get_cpu_var(zcache_preloads); - if (kp->obj == NULL) - kp->obj = obj; - else - kmem_cache_free(zcache_obj_cache, obj); - if (kp->page == NULL) - kp->page = page; - else - free_page((unsigned long)page); - ret = 0; -unlock_out: - spin_unlock(&zcache_direct_reclaim_lock); -out: - return ret; -} - -static void *zcache_get_free_page(void) -{ - struct zcache_preload *kp; - void *page; - - kp = &__get_cpu_var(zcache_preloads); - page = kp->page; - BUG_ON(page == NULL); - kp->page = NULL; - return page; -} - -static void zcache_free_page(void *p) -{ - free_page((unsigned long)p); -} - -/* - * zcache implementation for tmem host ops - */ - -static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool) -{ - struct tmem_objnode *objnode = NULL; - unsigned long count; - struct zcache_preload *kp; - - kp = &__get_cpu_var(zcache_preloads); - if (kp->nr <= 0) - goto out; - objnode = kp->objnodes[kp->nr - 1]; - BUG_ON(objnode == NULL); - kp->objnodes[kp->nr - 1] = NULL; - kp->nr--; - count = atomic_inc_return(&zcache_curr_objnode_count); - if (count > zcache_curr_objnode_count_max) - zcache_curr_objnode_count_max = count; -out: - return objnode; -} - -static void zcache_objnode_free(struct tmem_objnode *objnode, - struct tmem_pool *pool) -{ - atomic_dec(&zcache_curr_objnode_count); - BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0); - kmem_cache_free(zcache_objnode_cache, objnode); -} - -static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool) -{ - struct tmem_obj *obj = NULL; - unsigned long count; - struct zcache_preload *kp; - - kp = &__get_cpu_var(zcache_preloads); - obj = kp->obj; - BUG_ON(obj == NULL); - kp->obj = NULL; - count = atomic_inc_return(&zcache_curr_obj_count); - if (count > zcache_curr_obj_count_max) - zcache_curr_obj_count_max = count; - return obj; -} - -static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool) -{ - atomic_dec(&zcache_curr_obj_count); - BUG_ON(atomic_read(&zcache_curr_obj_count) < 0); - kmem_cache_free(zcache_obj_cache, obj); -} - -static struct tmem_hostops zcache_hostops = { - .obj_alloc = zcache_obj_alloc, - .obj_free = zcache_obj_free, - .objnode_alloc = zcache_objnode_alloc, - .objnode_free = zcache_objnode_free, -}; - -/* - * zcache implementations for PAM page descriptor ops - */ - -static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0); -static unsigned long zcache_curr_eph_pampd_count_max; -static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0); -static unsigned long zcache_curr_pers_pampd_count_max; - -/* forward reference */ -static int zcache_compress(struct page *from, void **out_va, size_t *out_len); - -static void *zcache_pampd_create(struct tmem_pool *pool, struct tmem_oid *oid, - uint32_t index, struct page *page) -{ - void *pampd = NULL, *cdata; - size_t clen; - int ret; - bool ephemeral = is_ephemeral(pool); - unsigned long count; - - if (ephemeral) { - ret = zcache_compress(page, &cdata, &clen); - if (ret == 0) - - goto out; - if (clen == 0 || clen > zbud_max_buddy_size()) { - zcache_compress_poor++; - goto out; - } - pampd = (void *)zbud_create(pool->pool_id, oid, index, - page, cdata, clen); - if (pampd != NULL) { - count = atomic_inc_return(&zcache_curr_eph_pampd_count); - if (count > zcache_curr_eph_pampd_count_max) - zcache_curr_eph_pampd_count_max = count; - } - } else { - /* - * FIXME: This is all the "policy" there is for now. - * 3/4 totpages should allow ~37% of RAM to be filled with - * compressed frontswap pages - */ - if (atomic_read(&zcache_curr_pers_pampd_count) > - 3 * totalram_pages / 4) - goto out; - ret = zcache_compress(page, &cdata, &clen); - if (ret == 0) - goto out; - if (clen > zv_max_page_size) { - zcache_compress_poor++; - goto out; - } - pampd = (void *)zv_create(zcache_client.xvpool, pool->pool_id, - oid, index, cdata, clen); - if (pampd == NULL) - goto out; - count = atomic_inc_return(&zcache_curr_pers_pampd_count); - if (count > zcache_curr_pers_pampd_count_max) - zcache_curr_pers_pampd_count_max = count; - } -out: - return pampd; -} - -/* - * fill the pageframe corresponding to the struct page with the data - * from the passed pampd - */ -static int zcache_pampd_get_data(struct page *page, void *pampd, - struct tmem_pool *pool) -{ - int ret = 0; - - if (is_ephemeral(pool)) - ret = zbud_decompress(page, pampd); - else - zv_decompress(page, pampd); - return ret; -} - -/* - * free the pampd and remove it from any zcache lists - * pampd must no longer be pointed to from any tmem data structures! - */ -static void zcache_pampd_free(void *pampd, struct tmem_pool *pool) -{ - if (is_ephemeral(pool)) { - zbud_free_and_delist((struct zbud_hdr *)pampd); - atomic_dec(&zcache_curr_eph_pampd_count); - BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0); - } else { - zv_free(zcache_client.xvpool, (struct zv_hdr *)pampd); - atomic_dec(&zcache_curr_pers_pampd_count); - BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0); - } -} - -static struct tmem_pamops zcache_pamops = { - .create = zcache_pampd_create, - .get_data = zcache_pampd_get_data, - .free = zcache_pampd_free, -}; - -/* - * zcache compression/decompression and related per-cpu stuff - */ - -#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS -#define LZO_DSTMEM_PAGE_ORDER 1 -static DEFINE_PER_CPU(unsigned char *, zcache_workmem); -static DEFINE_PER_CPU(unsigned char *, zcache_dstmem); - -static int zcache_compress(struct page *from, void **out_va, size_t *out_len) -{ - int ret = 0; - unsigned char *dmem = __get_cpu_var(zcache_dstmem); - unsigned char *wmem = __get_cpu_var(zcache_workmem); - char *from_va; - - BUG_ON(!irqs_disabled()); - if (unlikely(dmem == NULL || wmem == NULL)) - goto out; /* no buffer, so can't compress */ - from_va = kmap_atomic(from, KM_USER0); - mb(); - ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem); - BUG_ON(ret != LZO_E_OK); - *out_va = dmem; - kunmap_atomic(from_va, KM_USER0); - ret = 1; -out: - return ret; -} - - -static int zcache_cpu_notifier(struct notifier_block *nb, - unsigned long action, void *pcpu) -{ - int cpu = (long)pcpu; - struct zcache_preload *kp; - - switch (action) { - case CPU_UP_PREPARE: - per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages( - GFP_KERNEL | __GFP_REPEAT, - LZO_DSTMEM_PAGE_ORDER), - per_cpu(zcache_workmem, cpu) = - kzalloc(LZO1X_MEM_COMPRESS, - GFP_KERNEL | __GFP_REPEAT); - break; - case CPU_DEAD: - case CPU_UP_CANCELED: - free_pages((unsigned long)per_cpu(zcache_dstmem, cpu), - LZO_DSTMEM_PAGE_ORDER); - per_cpu(zcache_dstmem, cpu) = NULL; - kfree(per_cpu(zcache_workmem, cpu)); - per_cpu(zcache_workmem, cpu) = NULL; - kp = &per_cpu(zcache_preloads, cpu); - while (kp->nr) { - kmem_cache_free(zcache_objnode_cache, - kp->objnodes[kp->nr - 1]); - kp->objnodes[kp->nr - 1] = NULL; - kp->nr--; - } - kmem_cache_free(zcache_obj_cache, kp->obj); - free_page((unsigned long)kp->page); - break; - default: - break; - } - return NOTIFY_OK; -} - -static struct notifier_block zcache_cpu_notifier_block = { - .notifier_call = zcache_cpu_notifier -}; - -#ifdef CONFIG_SYSFS -#define ZCACHE_SYSFS_RO(_name) \ - static ssize_t zcache_##_name##_show(struct kobject *kobj, \ - struct kobj_attribute *attr, char *buf) \ - { \ - return sprintf(buf, "%lu\n", zcache_##_name); \ - } \ - static struct kobj_attribute zcache_##_name##_attr = { \ - .attr = { .name = __stringify(_name), .mode = 0444 }, \ - .show = zcache_##_name##_show, \ - } - -#define ZCACHE_SYSFS_RO_ATOMIC(_name) \ - static ssize_t zcache_##_name##_show(struct kobject *kobj, \ - struct kobj_attribute *attr, char *buf) \ - { \ - return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \ - } \ - static struct kobj_attribute zcache_##_name##_attr = { \ - .attr = { .name = __stringify(_name), .mode = 0444 }, \ - .show = zcache_##_name##_show, \ - } - -#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \ - static ssize_t zcache_##_name##_show(struct kobject *kobj, \ - struct kobj_attribute *attr, char *buf) \ - { \ - return _func(buf); \ - } \ - static struct kobj_attribute zcache_##_name##_attr = { \ - .attr = { .name = __stringify(_name), .mode = 0444 }, \ - .show = zcache_##_name##_show, \ - } - -ZCACHE_SYSFS_RO(curr_obj_count_max); -ZCACHE_SYSFS_RO(curr_objnode_count_max); -ZCACHE_SYSFS_RO(flush_total); -ZCACHE_SYSFS_RO(flush_found); -ZCACHE_SYSFS_RO(flobj_total); -ZCACHE_SYSFS_RO(flobj_found); -ZCACHE_SYSFS_RO(failed_eph_puts); -ZCACHE_SYSFS_RO(failed_pers_puts); -ZCACHE_SYSFS_RO(zbud_curr_zbytes); -ZCACHE_SYSFS_RO(zbud_cumul_zpages); -ZCACHE_SYSFS_RO(zbud_cumul_zbytes); -ZCACHE_SYSFS_RO(zbud_buddied_count); -ZCACHE_SYSFS_RO(zbpg_unused_list_count); -ZCACHE_SYSFS_RO(evicted_raw_pages); -ZCACHE_SYSFS_RO(evicted_unbuddied_pages); -ZCACHE_SYSFS_RO(evicted_buddied_pages); -ZCACHE_SYSFS_RO(failed_get_free_pages); -ZCACHE_SYSFS_RO(failed_alloc); -ZCACHE_SYSFS_RO(put_to_flush); -ZCACHE_SYSFS_RO(aborted_preload); -ZCACHE_SYSFS_RO(aborted_shrink); -ZCACHE_SYSFS_RO(compress_poor); -ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages); -ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages); -ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count); -ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count); -ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts, - zbud_show_unbuddied_list_counts); -ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts, - zbud_show_cumul_chunk_counts); - -static struct attribute *zcache_attrs[] = { - &zcache_curr_obj_count_attr.attr, - &zcache_curr_obj_count_max_attr.attr, - &zcache_curr_objnode_count_attr.attr, - &zcache_curr_objnode_count_max_attr.attr, - &zcache_flush_total_attr.attr, - &zcache_flobj_total_attr.attr, - &zcache_flush_found_attr.attr, - &zcache_flobj_found_attr.attr, - &zcache_failed_eph_puts_attr.attr, - &zcache_failed_pers_puts_attr.attr, - &zcache_compress_poor_attr.attr, - &zcache_zbud_curr_raw_pages_attr.attr, - &zcache_zbud_curr_zpages_attr.attr, - &zcache_zbud_curr_zbytes_attr.attr, - &zcache_zbud_cumul_zpages_attr.attr, - &zcache_zbud_cumul_zbytes_attr.attr, - &zcache_zbud_buddied_count_attr.attr, - &zcache_zbpg_unused_list_count_attr.attr, - &zcache_evicted_raw_pages_attr.attr, - &zcache_evicted_unbuddied_pages_attr.attr, - &zcache_evicted_buddied_pages_attr.attr, - &zcache_failed_get_free_pages_attr.attr, - &zcache_failed_alloc_attr.attr, - &zcache_put_to_flush_attr.attr, - &zcache_aborted_preload_attr.attr, - &zcache_aborted_shrink_attr.attr, - &zcache_zbud_unbuddied_list_counts_attr.attr, - &zcache_zbud_cumul_chunk_counts_attr.attr, - NULL, -}; - -static struct attribute_group zcache_attr_group = { - .attrs = zcache_attrs, - .name = "zcache", -}; - -#endif /* CONFIG_SYSFS */ -/* - * When zcache is disabled ("frozen"), pools can be created and destroyed, - * but all puts (and thus all other operations that require memory allocation) - * must fail. If zcache is unfrozen, accepts puts, then frozen again, - * data consistency requires all puts while frozen to be converted into - * flushes. - */ -static bool zcache_freeze; - -/* - * zcache shrinker interface (only useful for ephemeral pages, so zbud only) - */ -static int shrink_zcache_memory(struct shrinker *shrink, - struct shrink_control *sc) -{ - int ret = -1; - int nr = sc->nr_to_scan; - gfp_t gfp_mask = sc->gfp_mask; - - if (nr >= 0) { - if (!(gfp_mask & __GFP_FS)) - /* does this case really need to be skipped? */ - goto out; - if (spin_trylock(&zcache_direct_reclaim_lock)) { - zbud_evict_pages(nr); - spin_unlock(&zcache_direct_reclaim_lock); - } else - zcache_aborted_shrink++; - } - ret = (int)atomic_read(&zcache_zbud_curr_raw_pages); -out: - return ret; -} - -static struct shrinker zcache_shrinker = { - .shrink = shrink_zcache_memory, - .seeks = DEFAULT_SEEKS, -}; - -/* - * zcache shims between cleancache/frontswap ops and tmem - */ - -static int zcache_put_page(int pool_id, struct tmem_oid *oidp, - uint32_t index, struct page *page) -{ - struct tmem_pool *pool; - int ret = -1; - - BUG_ON(!irqs_disabled()); - pool = zcache_get_pool_by_id(pool_id); - if (unlikely(pool == NULL)) - goto out; - if (!zcache_freeze && zcache_do_preload(pool) == 0) { - /* preload does preempt_disable on success */ - ret = tmem_put(pool, oidp, index, page); - if (ret < 0) { - if (is_ephemeral(pool)) - zcache_failed_eph_puts++; - else - zcache_failed_pers_puts++; - } - zcache_put_pool(pool); - preempt_enable_no_resched(); - } else { - zcache_put_to_flush++; - if (atomic_read(&pool->obj_count) > 0) - /* the put fails whether the flush succeeds or not */ - (void)tmem_flush_page(pool, oidp, index); - zcache_put_pool(pool); - } -out: - return ret; -} - -static int zcache_get_page(int pool_id, struct tmem_oid *oidp, - uint32_t index, struct page *page) -{ - struct tmem_pool *pool; - int ret = -1; - unsigned long flags; - - local_irq_save(flags); - pool = zcache_get_pool_by_id(pool_id); - if (likely(pool != NULL)) { - if (atomic_read(&pool->obj_count) > 0) - ret = tmem_get(pool, oidp, index, page); - zcache_put_pool(pool); - } - local_irq_restore(flags); - return ret; -} - -static int zcache_flush_page(int pool_id, struct tmem_oid *oidp, uint32_t index) -{ - struct tmem_pool *pool; - int ret = -1; - unsigned long flags; - - local_irq_save(flags); - zcache_flush_total++; - pool = zcache_get_pool_by_id(pool_id); - if (likely(pool != NULL)) { - if (atomic_read(&pool->obj_count) > 0) - ret = tmem_flush_page(pool, oidp, index); - zcache_put_pool(pool); - } - if (ret >= 0) - zcache_flush_found++; - local_irq_restore(flags); - return ret; -} - -static int zcache_flush_object(int pool_id, struct tmem_oid *oidp) -{ - struct tmem_pool *pool; - int ret = -1; - unsigned long flags; - - local_irq_save(flags); - zcache_flobj_total++; - pool = zcache_get_pool_by_id(pool_id); - if (likely(pool != NULL)) { - if (atomic_read(&pool->obj_count) > 0) - ret = tmem_flush_object(pool, oidp); - zcache_put_pool(pool); - } - if (ret >= 0) - zcache_flobj_found++; - local_irq_restore(flags); - return ret; -} - -static int zcache_destroy_pool(int pool_id) -{ - struct tmem_pool *pool = NULL; - int ret = -1; - - if (pool_id < 0) - goto out; - pool = zcache_client.tmem_pools[pool_id]; - if (pool == NULL) - goto out; - zcache_client.tmem_pools[pool_id] = NULL; - /* wait for pool activity on other cpus to quiesce */ - while (atomic_read(&pool->refcount) != 0) - ; - local_bh_disable(); - ret = tmem_destroy_pool(pool); - local_bh_enable(); - kfree(pool); - pr_info("zcache: destroyed pool id=%d\n", pool_id); -out: - return ret; -} - -static int zcache_new_pool(uint32_t flags) -{ - int poolid = -1; - struct tmem_pool *pool; - - pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL); - if (pool == NULL) { - pr_info("zcache: pool creation failed: out of memory\n"); - goto out; - } - - for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++) - if (zcache_client.tmem_pools[poolid] == NULL) - break; - if (poolid >= MAX_POOLS_PER_CLIENT) { - pr_info("zcache: pool creation failed: max exceeded\n"); - kfree(pool); - poolid = -1; - goto out; - } - atomic_set(&pool->refcount, 0); - pool->client = &zcache_client; - pool->pool_id = poolid; - tmem_new_pool(pool, flags); - zcache_client.tmem_pools[poolid] = pool; - pr_info("zcache: created %s tmem pool, id=%d\n", - flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral", - poolid); -out: - return poolid; -} - -/********** - * Two kernel functionalities currently can be layered on top of tmem. - * These are "cleancache" which is used as a second-chance cache for clean - * page cache pages; and "frontswap" which is used for swap pages - * to avoid writes to disk. A generic "shim" is provided here for each - * to translate in-kernel semantics to zcache semantics. - */ - -#ifdef CONFIG_CLEANCACHE -static void zcache_cleancache_put_page(int pool_id, - struct cleancache_filekey key, - pgoff_t index, struct page *page) -{ - u32 ind = (u32) index; - struct tmem_oid oid = *(struct tmem_oid *)&key; - - if (likely(ind == index)) - (void)zcache_put_page(pool_id, &oid, index, page); -} - -static int zcache_cleancache_get_page(int pool_id, - struct cleancache_filekey key, - pgoff_t index, struct page *page) -{ - u32 ind = (u32) index; - struct tmem_oid oid = *(struct tmem_oid *)&key; - int ret = -1; - - if (likely(ind == index)) - ret = zcache_get_page(pool_id, &oid, index, page); - return ret; -} - -static void zcache_cleancache_flush_page(int pool_id, - struct cleancache_filekey key, - pgoff_t index) -{ - u32 ind = (u32) index; - struct tmem_oid oid = *(struct tmem_oid *)&key; - - if (likely(ind == index)) - (void)zcache_flush_page(pool_id, &oid, ind); -} - -static void zcache_cleancache_flush_inode(int pool_id, - struct cleancache_filekey key) -{ - struct tmem_oid oid = *(struct tmem_oid *)&key; - - (void)zcache_flush_object(pool_id, &oid); -} - -static void zcache_cleancache_flush_fs(int pool_id) -{ - if (pool_id >= 0) - (void)zcache_destroy_pool(pool_id); -} - -static int zcache_cleancache_init_fs(size_t pagesize) -{ - BUG_ON(sizeof(struct cleancache_filekey) != - sizeof(struct tmem_oid)); - BUG_ON(pagesize != PAGE_SIZE); - return zcache_new_pool(0); -} - -static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize) -{ - /* shared pools are unsupported and map to private */ - BUG_ON(sizeof(struct cleancache_filekey) != - sizeof(struct tmem_oid)); - BUG_ON(pagesize != PAGE_SIZE); - return zcache_new_pool(0); -} - -static struct cleancache_ops zcache_cleancache_ops = { - .put_page = zcache_cleancache_put_page, - .get_page = zcache_cleancache_get_page, - .flush_page = zcache_cleancache_flush_page, - .flush_inode = zcache_cleancache_flush_inode, - .flush_fs = zcache_cleancache_flush_fs, - .init_shared_fs = zcache_cleancache_init_shared_fs, - .init_fs = zcache_cleancache_init_fs -}; - -struct cleancache_ops zcache_cleancache_register_ops(void) -{ - struct cleancache_ops old_ops = - cleancache_register_ops(&zcache_cleancache_ops); - - return old_ops; -} -#endif - -#ifdef CONFIG_FRONTSWAP -/* a single tmem poolid is used for all frontswap "types" (swapfiles) */ -static int zcache_frontswap_poolid = -1; - -/* - * Swizzling increases objects per swaptype, increasing tmem concurrency - * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS - */ -#define SWIZ_BITS 4 -#define SWIZ_MASK ((1 << SWIZ_BITS) - 1) -#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK)) -#define iswiz(_ind) (_ind >> SWIZ_BITS) - -static inline struct tmem_oid oswiz(unsigned type, u32 ind) -{ - struct tmem_oid oid = { .oid = { 0 } }; - oid.oid[0] = _oswiz(type, ind); - return oid; -} - -static int zcache_frontswap_put_page(unsigned type, pgoff_t offset, - struct page *page) -{ - u64 ind64 = (u64)offset; - u32 ind = (u32)offset; - struct tmem_oid oid = oswiz(type, ind); - int ret = -1; - unsigned long flags; - - BUG_ON(!PageLocked(page)); - if (likely(ind64 == ind)) { - local_irq_save(flags); - ret = zcache_put_page(zcache_frontswap_poolid, &oid, - iswiz(ind), page); - local_irq_restore(flags); - } - return ret; -} - -/* returns 0 if the page was successfully gotten from frontswap, -1 if - * was not present (should never happen!) */ -static int zcache_frontswap_get_page(unsigned type, pgoff_t offset, - struct page *page) -{ - u64 ind64 = (u64)offset; - u32 ind = (u32)offset; - struct tmem_oid oid = oswiz(type, ind); - int ret = -1; - - BUG_ON(!PageLocked(page)); - if (likely(ind64 == ind)) - ret = zcache_get_page(zcache_frontswap_poolid, &oid, - iswiz(ind), page); - return ret; -} - -/* flush a single page from frontswap */ -static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset) -{ - u64 ind64 = (u64)offset; - u32 ind = (u32)offset; - struct tmem_oid oid = oswiz(type, ind); - - if (likely(ind64 == ind)) - (void)zcache_flush_page(zcache_frontswap_poolid, &oid, - iswiz(ind)); -} - -/* flush all pages from the passed swaptype */ -static void zcache_frontswap_flush_area(unsigned type) -{ - struct tmem_oid oid; - int ind; - - for (ind = SWIZ_MASK; ind >= 0; ind--) { - oid = oswiz(type, ind); - (void)zcache_flush_object(zcache_frontswap_poolid, &oid); - } -} - -static void zcache_frontswap_init(unsigned ignored) -{ - /* a single tmem poolid is used for all frontswap "types" (swapfiles) */ - if (zcache_frontswap_poolid < 0) - zcache_frontswap_poolid = zcache_new_pool(TMEM_POOL_PERSIST); -} - -static struct frontswap_ops zcache_frontswap_ops = { - .put_page = zcache_frontswap_put_page, - .get_page = zcache_frontswap_get_page, - .flush_page = zcache_frontswap_flush_page, - .flush_area = zcache_frontswap_flush_area, - .init = zcache_frontswap_init -}; - -struct frontswap_ops zcache_frontswap_register_ops(void) -{ - struct frontswap_ops old_ops = - frontswap_register_ops(&zcache_frontswap_ops); - - return old_ops; -} -#endif - -/* - * zcache initialization - * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR - * NOTHING HAPPENS! - */ - -static int zcache_enabled; - -static int __init enable_zcache(char *s) -{ - zcache_enabled = 1; - return 1; -} -__setup("zcache", enable_zcache); - -/* allow independent dynamic disabling of cleancache and frontswap */ - -static int use_cleancache = 1; - -static int __init no_cleancache(char *s) -{ - use_cleancache = 0; - return 1; -} - -__setup("nocleancache", no_cleancache); - -static int use_frontswap = 1; - -static int __init no_frontswap(char *s) -{ - use_frontswap = 0; - return 1; -} - -__setup("nofrontswap", no_frontswap); - -static int __init zcache_init(void) -{ -#ifdef CONFIG_SYSFS - int ret = 0; - - ret = sysfs_create_group(mm_kobj, &zcache_attr_group); - if (ret) { - pr_err("zcache: can't create sysfs\n"); - goto out; - } -#endif /* CONFIG_SYSFS */ -#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP) - if (zcache_enabled) { - unsigned int cpu; - - tmem_register_hostops(&zcache_hostops); - tmem_register_pamops(&zcache_pamops); - ret = register_cpu_notifier(&zcache_cpu_notifier_block); - if (ret) { - pr_err("zcache: can't register cpu notifier\n"); - goto out; - } - for_each_online_cpu(cpu) { - void *pcpu = (void *)(long)cpu; - zcache_cpu_notifier(&zcache_cpu_notifier_block, - CPU_UP_PREPARE, pcpu); - } - } - zcache_objnode_cache = kmem_cache_create("zcache_objnode", - sizeof(struct tmem_objnode), 0, 0, NULL); - zcache_obj_cache = kmem_cache_create("zcache_obj", - sizeof(struct tmem_obj), 0, 0, NULL); -#endif -#ifdef CONFIG_CLEANCACHE - if (zcache_enabled && use_cleancache) { - struct cleancache_ops old_ops; - - zbud_init(); - register_shrinker(&zcache_shrinker); - old_ops = zcache_cleancache_register_ops(); - pr_info("zcache: cleancache enabled using kernel " - "transcendent memory and compression buddies\n"); - if (old_ops.init_fs != NULL) - pr_warning("zcache: cleancache_ops overridden"); - } -#endif -#ifdef CONFIG_FRONTSWAP - if (zcache_enabled && use_frontswap) { - struct frontswap_ops old_ops; - - zcache_client.xvpool = xv_create_pool(); - if (zcache_client.xvpool == NULL) { - pr_err("zcache: can't create xvpool\n"); - goto out; - } - old_ops = zcache_frontswap_register_ops(); - pr_info("zcache: frontswap enabled using kernel " - "transcendent memory and xvmalloc\n"); - if (old_ops.init != NULL) - pr_warning("ktmem: frontswap_ops overridden"); - } -#endif -out: - return ret; -} - -module_init(zcache_init) diff -urN drivers.old//staging/zcache/zcache_drv.c drivers//staging/zcache/zcache_drv.c --- drivers.old//staging/zcache/zcache_drv.c 1970-01-01 01:00:00.000000000 +0100 +++ drivers//staging/zcache/zcache_drv.c 2011-07-25 12:02:14.032242244 +0200 @@ -0,0 +1,1661 @@ +/* + * zcache.c + * + * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp. + * Copyright (c) 2010,2011, Nitin Gupta + * + * Zcache provides an in-kernel "host implementation" for transcendent memory + * and, thus indirectly, for cleancache and frontswap. Zcache includes two + * page-accessible memory [1] interfaces, both utilizing lzo1x compression: + * 1) "compression buddies" ("zbud") is used for ephemeral pages + * 2) xvmalloc is used for persistent pages. + * Xvmalloc (based on the TLSF allocator) has very low fragmentation + * so maximizes space efficiency, while zbud allows pairs (and potentially, + * in the future, more than a pair of) compressed pages to be closely linked + * so that reclaiming can be done via the kernel's physical-page-oriented + * "shrinker" interface. + * + * [1] For a definition of page-accessible memory (aka PAM), see: + * http://marc.info/?l=linux-mm&m=127811271605009 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include "tmem.h" + +#include "../zram/xvmalloc.h" /* if built in drivers/staging */ + +#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP)) +#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP" +#endif +#ifdef CONFIG_CLEANCACHE +#include +#endif +#ifdef CONFIG_FRONTSWAP +#include +#endif + +#if 0 +/* this is more aggressive but may cause other problems? */ +#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN) +#else +#define ZCACHE_GFP_MASK \ + (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC) +#endif + +/********** + * Compression buddies ("zbud") provides for packing two (or, possibly + * in the future, more) compressed ephemeral pages into a single "raw" + * (physical) page and tracking them with data structures so that + * the raw pages can be easily reclaimed. + * + * A zbud page ("zbpg") is an aligned page containing a list_head, + * a lock, and two "zbud headers". The remainder of the physical + * page is divided up into aligned 64-byte "chunks" which contain + * the compressed data for zero, one, or two zbuds. Each zbpg + * resides on: (1) an "unused list" if it has no zbuds; (2) a + * "buddied" list if it is fully populated with two zbuds; or + * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks + * the one unbuddied zbud uses. The data inside a zbpg cannot be + * read or written unless the zbpg's lock is held. + */ + +#define ZBH_SENTINEL 0x43214321 +#define ZBPG_SENTINEL 0xdeadbeef + +#define ZBUD_MAX_BUDS 2 + +struct zbud_hdr { + uint32_t pool_id; + struct tmem_oid oid; + uint32_t index; + uint16_t size; /* compressed size in bytes, zero means unused */ + DECL_SENTINEL +}; + +struct zbud_page { + struct list_head bud_list; + spinlock_t lock; + struct zbud_hdr buddy[ZBUD_MAX_BUDS]; + DECL_SENTINEL + /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */ +}; + +#define CHUNK_SHIFT 6 +#define CHUNK_SIZE (1 << CHUNK_SHIFT) +#define CHUNK_MASK (~(CHUNK_SIZE-1)) +#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \ + CHUNK_MASK) >> CHUNK_SHIFT) +#define MAX_CHUNK (NCHUNKS-1) + +static struct { + struct list_head list; + unsigned count; +} zbud_unbuddied[NCHUNKS]; +/* list N contains pages with N chunks USED and NCHUNKS-N unused */ +/* element 0 is never used but optimizing that isn't worth it */ +static unsigned long zbud_cumul_chunk_counts[NCHUNKS]; + +struct list_head zbud_buddied_list; +static unsigned long zcache_zbud_buddied_count; + +/* protects the buddied list and all unbuddied lists */ +static DEFINE_SPINLOCK(zbud_budlists_spinlock); + +static LIST_HEAD(zbpg_unused_list); +static unsigned long zcache_zbpg_unused_list_count; + +/* protects the unused page list */ +static DEFINE_SPINLOCK(zbpg_unused_list_spinlock); + +static atomic_t zcache_zbud_curr_raw_pages; +static atomic_t zcache_zbud_curr_zpages; +static unsigned long zcache_zbud_curr_zbytes; +static unsigned long zcache_zbud_cumul_zpages; +static unsigned long zcache_zbud_cumul_zbytes; +static unsigned long zcache_compress_poor; + +/* forward references */ +static void *zcache_get_free_page(void); +static void zcache_free_page(void *p); + +/* + * zbud helper functions + */ + +static inline unsigned zbud_max_buddy_size(void) +{ + return MAX_CHUNK << CHUNK_SHIFT; +} + +static inline unsigned zbud_size_to_chunks(unsigned size) +{ + BUG_ON(size == 0 || size > zbud_max_buddy_size()); + return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT; +} + +static inline int zbud_budnum(struct zbud_hdr *zh) +{ + unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1); + struct zbud_page *zbpg = NULL; + unsigned budnum = -1U; + int i; + + for (i = 0; i < ZBUD_MAX_BUDS; i++) + if (offset == offsetof(typeof(*zbpg), buddy[i])) { + budnum = i; + break; + } + BUG_ON(budnum == -1U); + return budnum; +} + +static char *zbud_data(struct zbud_hdr *zh, unsigned size) +{ + struct zbud_page *zbpg; + char *p; + unsigned budnum; + + ASSERT_SENTINEL(zh, ZBH); + budnum = zbud_budnum(zh); + BUG_ON(size == 0 || size > zbud_max_buddy_size()); + zbpg = container_of(zh, struct zbud_page, buddy[budnum]); + ASSERT_SPINLOCK(&zbpg->lock); + p = (char *)zbpg; + if (budnum == 0) + p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) & + CHUNK_MASK); + else if (budnum == 1) + p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK); + return p; +} + +/* + * zbud raw page management + */ + +static struct zbud_page *zbud_alloc_raw_page(void) +{ + struct zbud_page *zbpg = NULL; + struct zbud_hdr *zh0, *zh1; + bool recycled = 0; + + /* if any pages on the zbpg list, use one */ + spin_lock(&zbpg_unused_list_spinlock); + if (!list_empty(&zbpg_unused_list)) { + zbpg = list_first_entry(&zbpg_unused_list, + struct zbud_page, bud_list); + list_del_init(&zbpg->bud_list); + zcache_zbpg_unused_list_count--; + recycled = 1; + } + spin_unlock(&zbpg_unused_list_spinlock); + if (zbpg == NULL) + /* none on zbpg list, try to get a kernel page */ + zbpg = zcache_get_free_page(); + if (likely(zbpg != NULL)) { + INIT_LIST_HEAD(&zbpg->bud_list); + zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1]; + spin_lock_init(&zbpg->lock); + if (recycled) { + ASSERT_INVERTED_SENTINEL(zbpg, ZBPG); + SET_SENTINEL(zbpg, ZBPG); + BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid)); + BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid)); + } else { + atomic_inc(&zcache_zbud_curr_raw_pages); + INIT_LIST_HEAD(&zbpg->bud_list); + SET_SENTINEL(zbpg, ZBPG); + zh0->size = 0; zh1->size = 0; + tmem_oid_set_invalid(&zh0->oid); + tmem_oid_set_invalid(&zh1->oid); + } + } + return zbpg; +} + +static void zbud_free_raw_page(struct zbud_page *zbpg) +{ + struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1]; + + ASSERT_SENTINEL(zbpg, ZBPG); + BUG_ON(!list_empty(&zbpg->bud_list)); + ASSERT_SPINLOCK(&zbpg->lock); + BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid)); + BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid)); + INVERT_SENTINEL(zbpg, ZBPG); + spin_unlock(&zbpg->lock); + spin_lock(&zbpg_unused_list_spinlock); + list_add(&zbpg->bud_list, &zbpg_unused_list); + zcache_zbpg_unused_list_count++; + spin_unlock(&zbpg_unused_list_spinlock); +} + +/* + * core zbud handling routines + */ + +static unsigned zbud_free(struct zbud_hdr *zh) +{ + unsigned size; + + ASSERT_SENTINEL(zh, ZBH); + BUG_ON(!tmem_oid_valid(&zh->oid)); + size = zh->size; + BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size()); + zh->size = 0; + tmem_oid_set_invalid(&zh->oid); + INVERT_SENTINEL(zh, ZBH); + zcache_zbud_curr_zbytes -= size; + atomic_dec(&zcache_zbud_curr_zpages); + return size; +} + +static void zbud_free_and_delist(struct zbud_hdr *zh) +{ + unsigned chunks; + struct zbud_hdr *zh_other; + unsigned budnum = zbud_budnum(zh), size; + struct zbud_page *zbpg = + container_of(zh, struct zbud_page, buddy[budnum]); + + spin_lock(&zbpg->lock); + if (list_empty(&zbpg->bud_list)) { + /* ignore zombie page... see zbud_evict_pages() */ + spin_unlock(&zbpg->lock); + return; + } + size = zbud_free(zh); + ASSERT_SPINLOCK(&zbpg->lock); + zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0]; + if (zh_other->size == 0) { /* was unbuddied: unlist and free */ + chunks = zbud_size_to_chunks(size) ; + spin_lock(&zbud_budlists_spinlock); + BUG_ON(list_empty(&zbud_unbuddied[chunks].list)); + list_del_init(&zbpg->bud_list); + zbud_unbuddied[chunks].count--; + spin_unlock(&zbud_budlists_spinlock); + zbud_free_raw_page(zbpg); + } else { /* was buddied: move remaining buddy to unbuddied list */ + chunks = zbud_size_to_chunks(zh_other->size) ; + spin_lock(&zbud_budlists_spinlock); + list_del_init(&zbpg->bud_list); + zcache_zbud_buddied_count--; + list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list); + zbud_unbuddied[chunks].count++; + spin_unlock(&zbud_budlists_spinlock); + spin_unlock(&zbpg->lock); + } +} + +static struct zbud_hdr *zbud_create(uint32_t pool_id, struct tmem_oid *oid, + uint32_t index, struct page *page, + void *cdata, unsigned size) +{ + struct zbud_hdr *zh0, *zh1, *zh = NULL; + struct zbud_page *zbpg = NULL, *ztmp; + unsigned nchunks; + char *to; + int i, found_good_buddy = 0; + + nchunks = zbud_size_to_chunks(size) ; + for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) { + spin_lock(&zbud_budlists_spinlock); + if (!list_empty(&zbud_unbuddied[i].list)) { + list_for_each_entry_safe(zbpg, ztmp, + &zbud_unbuddied[i].list, bud_list) { + if (spin_trylock(&zbpg->lock)) { + found_good_buddy = i; + goto found_unbuddied; + } + } + } + spin_unlock(&zbud_budlists_spinlock); + } + /* didn't find a good buddy, try allocating a new page */ + zbpg = zbud_alloc_raw_page(); + if (unlikely(zbpg == NULL)) + goto out; + /* ok, have a page, now compress the data before taking locks */ + spin_lock(&zbpg->lock); + spin_lock(&zbud_budlists_spinlock); + list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list); + zbud_unbuddied[nchunks].count++; + zh = &zbpg->buddy[0]; + goto init_zh; + +found_unbuddied: + ASSERT_SPINLOCK(&zbpg->lock); + zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1]; + BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0))); + if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */ + ASSERT_SENTINEL(zh0, ZBH); + zh = zh1; + } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */ + ASSERT_SENTINEL(zh1, ZBH); + zh = zh0; + } else + BUG(); + list_del_init(&zbpg->bud_list); + zbud_unbuddied[found_good_buddy].count--; + list_add_tail(&zbpg->bud_list, &zbud_buddied_list); + zcache_zbud_buddied_count++; + +init_zh: + SET_SENTINEL(zh, ZBH); + zh->size = size; + zh->index = index; + zh->oid = *oid; + zh->pool_id = pool_id; + /* can wait to copy the data until the list locks are dropped */ + spin_unlock(&zbud_budlists_spinlock); + + to = zbud_data(zh, size); + memcpy(to, cdata, size); + spin_unlock(&zbpg->lock); + zbud_cumul_chunk_counts[nchunks]++; + atomic_inc(&zcache_zbud_curr_zpages); + zcache_zbud_cumul_zpages++; + zcache_zbud_curr_zbytes += size; + zcache_zbud_cumul_zbytes += size; +out: + return zh; +} + +static int zbud_decompress(struct page *page, struct zbud_hdr *zh) +{ + struct zbud_page *zbpg; + unsigned budnum = zbud_budnum(zh); + size_t out_len = PAGE_SIZE; + char *to_va, *from_va; + unsigned size; + int ret = 0; + + zbpg = container_of(zh, struct zbud_page, buddy[budnum]); + spin_lock(&zbpg->lock); + if (list_empty(&zbpg->bud_list)) { + /* ignore zombie page... see zbud_evict_pages() */ + ret = -EINVAL; + goto out; + } + ASSERT_SENTINEL(zh, ZBH); + BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size()); + to_va = kmap_atomic(page, KM_USER0); + size = zh->size; + from_va = zbud_data(zh, size); + ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len); + BUG_ON(ret != LZO_E_OK); + BUG_ON(out_len != PAGE_SIZE); + kunmap_atomic(to_va, KM_USER0); +out: + spin_unlock(&zbpg->lock); + return ret; +} + +/* + * The following routines handle shrinking of ephemeral pages by evicting + * pages "least valuable" first. + */ + +static unsigned long zcache_evicted_raw_pages; +static unsigned long zcache_evicted_buddied_pages; +static unsigned long zcache_evicted_unbuddied_pages; + +static struct tmem_pool *zcache_get_pool_by_id(uint32_t poolid); +static void zcache_put_pool(struct tmem_pool *pool); + +/* + * Flush and free all zbuds in a zbpg, then free the pageframe + */ +static void zbud_evict_zbpg(struct zbud_page *zbpg) +{ + struct zbud_hdr *zh; + int i, j; + uint32_t pool_id[ZBUD_MAX_BUDS], index[ZBUD_MAX_BUDS]; + struct tmem_oid oid[ZBUD_MAX_BUDS]; + struct tmem_pool *pool; + + ASSERT_SPINLOCK(&zbpg->lock); + BUG_ON(!list_empty(&zbpg->bud_list)); + for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) { + zh = &zbpg->buddy[i]; + if (zh->size) { + pool_id[j] = zh->pool_id; + oid[j] = zh->oid; + index[j] = zh->index; + j++; + zbud_free(zh); + } + } + spin_unlock(&zbpg->lock); + for (i = 0; i < j; i++) { + pool = zcache_get_pool_by_id(pool_id[i]); + if (pool != NULL) { + tmem_flush_page(pool, &oid[i], index[i]); + zcache_put_pool(pool); + } + } + ASSERT_SENTINEL(zbpg, ZBPG); + spin_lock(&zbpg->lock); + zbud_free_raw_page(zbpg); +} + +/* + * Free nr pages. This code is funky because we want to hold the locks + * protecting various lists for as short a time as possible, and in some + * circumstances the list may change asynchronously when the list lock is + * not held. In some cases we also trylock not only to avoid waiting on a + * page in use by another cpu, but also to avoid potential deadlock due to + * lock inversion. + */ +static void zbud_evict_pages(int nr) +{ + struct zbud_page *zbpg; + int i; + + /* first try freeing any pages on unused list */ +retry_unused_list: + spin_lock_bh(&zbpg_unused_list_spinlock); + if (!list_empty(&zbpg_unused_list)) { + /* can't walk list here, since it may change when unlocked */ + zbpg = list_first_entry(&zbpg_unused_list, + struct zbud_page, bud_list); + list_del_init(&zbpg->bud_list); + zcache_zbpg_unused_list_count--; + atomic_dec(&zcache_zbud_curr_raw_pages); + spin_unlock_bh(&zbpg_unused_list_spinlock); + zcache_free_page(zbpg); + zcache_evicted_raw_pages++; + if (--nr <= 0) + goto out; + goto retry_unused_list; + } + spin_unlock_bh(&zbpg_unused_list_spinlock); + + /* now try freeing unbuddied pages, starting with least space avail */ + for (i = 0; i < MAX_CHUNK; i++) { +retry_unbud_list_i: + spin_lock_bh(&zbud_budlists_spinlock); + if (list_empty(&zbud_unbuddied[i].list)) { + spin_unlock_bh(&zbud_budlists_spinlock); + continue; + } + list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) { + if (unlikely(!spin_trylock(&zbpg->lock))) + continue; + list_del_init(&zbpg->bud_list); + zbud_unbuddied[i].count--; + spin_unlock(&zbud_budlists_spinlock); + zcache_evicted_unbuddied_pages++; + /* want budlists unlocked when doing zbpg eviction */ + zbud_evict_zbpg(zbpg); + local_bh_enable(); + if (--nr <= 0) + goto out; + goto retry_unbud_list_i; + } + spin_unlock_bh(&zbud_budlists_spinlock); + } + + /* as a last resort, free buddied pages */ +retry_bud_list: + spin_lock_bh(&zbud_budlists_spinlock); + if (list_empty(&zbud_buddied_list)) { + spin_unlock_bh(&zbud_budlists_spinlock); + goto out; + } + list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) { + if (unlikely(!spin_trylock(&zbpg->lock))) + continue; + list_del_init(&zbpg->bud_list); + zcache_zbud_buddied_count--; + spin_unlock(&zbud_budlists_spinlock); + zcache_evicted_buddied_pages++; + /* want budlists unlocked when doing zbpg eviction */ + zbud_evict_zbpg(zbpg); + local_bh_enable(); + if (--nr <= 0) + goto out; + goto retry_bud_list; + } + spin_unlock_bh(&zbud_budlists_spinlock); +out: + return; +} + +static void zbud_init(void) +{ + int i; + + INIT_LIST_HEAD(&zbud_buddied_list); + zcache_zbud_buddied_count = 0; + for (i = 0; i < NCHUNKS; i++) { + INIT_LIST_HEAD(&zbud_unbuddied[i].list); + zbud_unbuddied[i].count = 0; + } +} + +#ifdef CONFIG_SYSFS +/* + * These sysfs routines show a nice distribution of how many zbpg's are + * currently (and have ever been placed) in each unbuddied list. It's fun + * to watch but can probably go away before final merge. + */ +static int zbud_show_unbuddied_list_counts(char *buf) +{ + int i; + char *p = buf; + + for (i = 0; i < NCHUNKS - 1; i++) + p += sprintf(p, "%u ", zbud_unbuddied[i].count); + p += sprintf(p, "%d\n", zbud_unbuddied[i].count); + return p - buf; +} + +static int zbud_show_cumul_chunk_counts(char *buf) +{ + unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0; + unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0; + unsigned long total_chunks_lte_42 = 0; + char *p = buf; + + for (i = 0; i < NCHUNKS; i++) { + p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]); + chunks += zbud_cumul_chunk_counts[i]; + total_chunks += zbud_cumul_chunk_counts[i]; + sum_total_chunks += i * zbud_cumul_chunk_counts[i]; + if (i == 21) + total_chunks_lte_21 = total_chunks; + if (i == 32) + total_chunks_lte_32 = total_chunks; + if (i == 42) + total_chunks_lte_42 = total_chunks; + } + p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n", + total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42, + chunks == 0 ? 0 : sum_total_chunks / chunks); + return p - buf; +} +#endif + +/********** + * This "zv" PAM implementation combines the TLSF-based xvMalloc + * with lzo1x compression to maximize the amount of data that can + * be packed into a physical page. + * + * Zv represents a PAM page with the index and object (plus a "size" value + * necessary for decompression) immediately preceding the compressed data. + */ + +#define ZVH_SENTINEL 0x43214321 + +struct zv_hdr { + uint32_t pool_id; + struct tmem_oid oid; + uint32_t index; + DECL_SENTINEL +}; + +static const int zv_max_page_size = (PAGE_SIZE / 8) * 7; + +static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id, + struct tmem_oid *oid, uint32_t index, + void *cdata, unsigned clen) +{ + struct page *page; + struct zv_hdr *zv = NULL; + uint32_t offset; + int ret; + + BUG_ON(!irqs_disabled()); + ret = xv_malloc(xvpool, clen + sizeof(struct zv_hdr), + &page, &offset, ZCACHE_GFP_MASK); + if (unlikely(ret)) + goto out; + zv = kmap_atomic(page, KM_USER0) + offset; + zv->index = index; + zv->oid = *oid; + zv->pool_id = pool_id; + SET_SENTINEL(zv, ZVH); + memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen); + kunmap_atomic(zv, KM_USER0); +out: + return zv; +} + +static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv) +{ + unsigned long flags; + struct page *page; + uint32_t offset; + uint16_t size; + + ASSERT_SENTINEL(zv, ZVH); + size = xv_get_object_size(zv) - sizeof(*zv); + BUG_ON(size == 0 || size > zv_max_page_size); + INVERT_SENTINEL(zv, ZVH); + page = virt_to_page(zv); + offset = (unsigned long)zv & ~PAGE_MASK; + local_irq_save(flags); + xv_free(xvpool, page, offset); + local_irq_restore(flags); +} + +static void zv_decompress(struct page *page, struct zv_hdr *zv) +{ + size_t clen = PAGE_SIZE; + char *to_va; + unsigned size; + int ret; + + ASSERT_SENTINEL(zv, ZVH); + size = xv_get_object_size(zv) - sizeof(*zv); + BUG_ON(size == 0 || size > zv_max_page_size); + to_va = kmap_atomic(page, KM_USER0); + ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv), + size, to_va, &clen); + kunmap_atomic(to_va, KM_USER0); + BUG_ON(ret != LZO_E_OK); + BUG_ON(clen != PAGE_SIZE); +} + +/* + * zcache core code starts here + */ + +/* useful stats not collected by cleancache or frontswap */ +static unsigned long zcache_flush_total; +static unsigned long zcache_flush_found; +static unsigned long zcache_flobj_total; +static unsigned long zcache_flobj_found; +static unsigned long zcache_failed_eph_puts; +static unsigned long zcache_failed_pers_puts; + +#define MAX_POOLS_PER_CLIENT 16 + +static struct { + struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT]; + struct xv_pool *xvpool; +} zcache_client; + +/* + * Tmem operations assume the poolid implies the invoking client. + * Zcache only has one client (the kernel itself), so translate + * the poolid into the tmem_pool allocated for it. A KVM version + * of zcache would have one client per guest and each client might + * have a poolid==N. + */ +static struct tmem_pool *zcache_get_pool_by_id(uint32_t poolid) +{ + struct tmem_pool *pool = NULL; + + if (poolid >= 0) { + pool = zcache_client.tmem_pools[poolid]; + if (pool != NULL) + atomic_inc(&pool->refcount); + } + return pool; +} + +static void zcache_put_pool(struct tmem_pool *pool) +{ + if (pool != NULL) + atomic_dec(&pool->refcount); +} + +/* counters for debugging */ +static unsigned long zcache_failed_get_free_pages; +static unsigned long zcache_failed_alloc; +static unsigned long zcache_put_to_flush; +static unsigned long zcache_aborted_preload; +static unsigned long zcache_aborted_shrink; + +/* + * Ensure that memory allocation requests in zcache don't result + * in direct reclaim requests via the shrinker, which would cause + * an infinite loop. Maybe a GFP flag would be better? + */ +static DEFINE_SPINLOCK(zcache_direct_reclaim_lock); + +/* + * for now, used named slabs so can easily track usage; later can + * either just use kmalloc, or perhaps add a slab-like allocator + * to more carefully manage total memory utilization + */ +static struct kmem_cache *zcache_objnode_cache; +static struct kmem_cache *zcache_obj_cache; +static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0); +static unsigned long zcache_curr_obj_count_max; +static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0); +static unsigned long zcache_curr_objnode_count_max; + +/* + * to avoid memory allocation recursion (e.g. due to direct reclaim), we + * preload all necessary data structures so the hostops callbacks never + * actually do a malloc + */ +struct zcache_preload { + void *page; + struct tmem_obj *obj; + int nr; + struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH]; +}; +static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, }; + +static int zcache_do_preload(struct tmem_pool *pool) +{ + struct zcache_preload *kp; + struct tmem_objnode *objnode; + struct tmem_obj *obj; + void *page; + int ret = -ENOMEM; + + if (unlikely(zcache_objnode_cache == NULL)) + goto out; + if (unlikely(zcache_obj_cache == NULL)) + goto out; + if (!spin_trylock(&zcache_direct_reclaim_lock)) { + zcache_aborted_preload++; + goto out; + } + preempt_disable(); + kp = &__get_cpu_var(zcache_preloads); + while (kp->nr < ARRAY_SIZE(kp->objnodes)) { + preempt_enable_no_resched(); + objnode = kmem_cache_alloc(zcache_objnode_cache, + ZCACHE_GFP_MASK); + if (unlikely(objnode == NULL)) { + zcache_failed_alloc++; + goto unlock_out; + } + preempt_disable(); + kp = &__get_cpu_var(zcache_preloads); + if (kp->nr < ARRAY_SIZE(kp->objnodes)) + kp->objnodes[kp->nr++] = objnode; + else + kmem_cache_free(zcache_objnode_cache, objnode); + } + preempt_enable_no_resched(); + obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK); + if (unlikely(obj == NULL)) { + zcache_failed_alloc++; + goto unlock_out; + } + page = (void *)__get_free_page(ZCACHE_GFP_MASK); + if (unlikely(page == NULL)) { + zcache_failed_get_free_pages++; + kmem_cache_free(zcache_obj_cache, obj); + goto unlock_out; + } + preempt_disable(); + kp = &__get_cpu_var(zcache_preloads); + if (kp->obj == NULL) + kp->obj = obj; + else + kmem_cache_free(zcache_obj_cache, obj); + if (kp->page == NULL) + kp->page = page; + else + free_page((unsigned long)page); + ret = 0; +unlock_out: + spin_unlock(&zcache_direct_reclaim_lock); +out: + return ret; +} + +static void *zcache_get_free_page(void) +{ + struct zcache_preload *kp; + void *page; + + kp = &__get_cpu_var(zcache_preloads); + page = kp->page; + BUG_ON(page == NULL); + kp->page = NULL; + return page; +} + +static void zcache_free_page(void *p) +{ + free_page((unsigned long)p); +} + +/* + * zcache implementation for tmem host ops + */ + +static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool) +{ + struct tmem_objnode *objnode = NULL; + unsigned long count; + struct zcache_preload *kp; + + kp = &__get_cpu_var(zcache_preloads); + if (kp->nr <= 0) + goto out; + objnode = kp->objnodes[kp->nr - 1]; + BUG_ON(objnode == NULL); + kp->objnodes[kp->nr - 1] = NULL; + kp->nr--; + count = atomic_inc_return(&zcache_curr_objnode_count); + if (count > zcache_curr_objnode_count_max) + zcache_curr_objnode_count_max = count; +out: + return objnode; +} + +static void zcache_objnode_free(struct tmem_objnode *objnode, + struct tmem_pool *pool) +{ + atomic_dec(&zcache_curr_objnode_count); + BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0); + kmem_cache_free(zcache_objnode_cache, objnode); +} + +static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool) +{ + struct tmem_obj *obj = NULL; + unsigned long count; + struct zcache_preload *kp; + + kp = &__get_cpu_var(zcache_preloads); + obj = kp->obj; + BUG_ON(obj == NULL); + kp->obj = NULL; + count = atomic_inc_return(&zcache_curr_obj_count); + if (count > zcache_curr_obj_count_max) + zcache_curr_obj_count_max = count; + return obj; +} + +static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool) +{ + atomic_dec(&zcache_curr_obj_count); + BUG_ON(atomic_read(&zcache_curr_obj_count) < 0); + kmem_cache_free(zcache_obj_cache, obj); +} + +static struct tmem_hostops zcache_hostops = { + .obj_alloc = zcache_obj_alloc, + .obj_free = zcache_obj_free, + .objnode_alloc = zcache_objnode_alloc, + .objnode_free = zcache_objnode_free, +}; + +/* + * zcache implementations for PAM page descriptor ops + */ + +static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0); +static unsigned long zcache_curr_eph_pampd_count_max; +static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0); +static unsigned long zcache_curr_pers_pampd_count_max; + +/* forward reference */ +static int zcache_compress(struct page *from, void **out_va, size_t *out_len); + +static void *zcache_pampd_create(struct tmem_pool *pool, struct tmem_oid *oid, + uint32_t index, struct page *page) +{ + void *pampd = NULL, *cdata; + size_t clen; + int ret; + bool ephemeral = is_ephemeral(pool); + unsigned long count; + + if (ephemeral) { + ret = zcache_compress(page, &cdata, &clen); + if (ret == 0) + + goto out; + if (clen == 0 || clen > zbud_max_buddy_size()) { + zcache_compress_poor++; + goto out; + } + pampd = (void *)zbud_create(pool->pool_id, oid, index, + page, cdata, clen); + if (pampd != NULL) { + count = atomic_inc_return(&zcache_curr_eph_pampd_count); + if (count > zcache_curr_eph_pampd_count_max) + zcache_curr_eph_pampd_count_max = count; + } + } else { + /* + * FIXME: This is all the "policy" there is for now. + * 3/4 totpages should allow ~37% of RAM to be filled with + * compressed frontswap pages + */ + if (atomic_read(&zcache_curr_pers_pampd_count) > + 3 * totalram_pages / 4) + goto out; + ret = zcache_compress(page, &cdata, &clen); + if (ret == 0) + goto out; + if (clen > zv_max_page_size) { + zcache_compress_poor++; + goto out; + } + pampd = (void *)zv_create(zcache_client.xvpool, pool->pool_id, + oid, index, cdata, clen); + if (pampd == NULL) + goto out; + count = atomic_inc_return(&zcache_curr_pers_pampd_count); + if (count > zcache_curr_pers_pampd_count_max) + zcache_curr_pers_pampd_count_max = count; + } +out: + return pampd; +} + +/* + * fill the pageframe corresponding to the struct page with the data + * from the passed pampd + */ +static int zcache_pampd_get_data(struct page *page, void *pampd, + struct tmem_pool *pool) +{ + int ret = 0; + + if (is_ephemeral(pool)) + ret = zbud_decompress(page, pampd); + else + zv_decompress(page, pampd); + return ret; +} + +/* + * free the pampd and remove it from any zcache lists + * pampd must no longer be pointed to from any tmem data structures! + */ +static void zcache_pampd_free(void *pampd, struct tmem_pool *pool) +{ + if (is_ephemeral(pool)) { + zbud_free_and_delist((struct zbud_hdr *)pampd); + atomic_dec(&zcache_curr_eph_pampd_count); + BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0); + } else { + zv_free(zcache_client.xvpool, (struct zv_hdr *)pampd); + atomic_dec(&zcache_curr_pers_pampd_count); + BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0); + } +} + +static struct tmem_pamops zcache_pamops = { + .create = zcache_pampd_create, + .get_data = zcache_pampd_get_data, + .free = zcache_pampd_free, +}; + +/* + * zcache compression/decompression and related per-cpu stuff + */ + +#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS +#define LZO_DSTMEM_PAGE_ORDER 1 +static DEFINE_PER_CPU(unsigned char *, zcache_workmem); +static DEFINE_PER_CPU(unsigned char *, zcache_dstmem); + +static int zcache_compress(struct page *from, void **out_va, size_t *out_len) +{ + int ret = 0; + unsigned char *dmem = __get_cpu_var(zcache_dstmem); + unsigned char *wmem = __get_cpu_var(zcache_workmem); + char *from_va; + + BUG_ON(!irqs_disabled()); + if (unlikely(dmem == NULL || wmem == NULL)) + goto out; /* no buffer, so can't compress */ + from_va = kmap_atomic(from, KM_USER0); + mb(); + ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem); + BUG_ON(ret != LZO_E_OK); + *out_va = dmem; + kunmap_atomic(from_va, KM_USER0); + ret = 1; +out: + return ret; +} + + +static int zcache_cpu_notifier(struct notifier_block *nb, + unsigned long action, void *pcpu) +{ + int cpu = (long)pcpu; + struct zcache_preload *kp; + + switch (action) { + case CPU_UP_PREPARE: + per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages( + GFP_KERNEL | __GFP_REPEAT, + LZO_DSTMEM_PAGE_ORDER), + per_cpu(zcache_workmem, cpu) = + kzalloc(LZO1X_MEM_COMPRESS, + GFP_KERNEL | __GFP_REPEAT); + break; + case CPU_DEAD: + case CPU_UP_CANCELED: + free_pages((unsigned long)per_cpu(zcache_dstmem, cpu), + LZO_DSTMEM_PAGE_ORDER); + per_cpu(zcache_dstmem, cpu) = NULL; + kfree(per_cpu(zcache_workmem, cpu)); + per_cpu(zcache_workmem, cpu) = NULL; + kp = &per_cpu(zcache_preloads, cpu); + while (kp->nr) { + kmem_cache_free(zcache_objnode_cache, + kp->objnodes[kp->nr - 1]); + kp->objnodes[kp->nr - 1] = NULL; + kp->nr--; + } + kmem_cache_free(zcache_obj_cache, kp->obj); + free_page((unsigned long)kp->page); + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block zcache_cpu_notifier_block = { + .notifier_call = zcache_cpu_notifier +}; + +#ifdef CONFIG_SYSFS +#define ZCACHE_SYSFS_RO(_name) \ + static ssize_t zcache_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return sprintf(buf, "%lu\n", zcache_##_name); \ + } \ + static struct kobj_attribute zcache_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0444 }, \ + .show = zcache_##_name##_show, \ + } + +#define ZCACHE_SYSFS_RO_ATOMIC(_name) \ + static ssize_t zcache_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \ + } \ + static struct kobj_attribute zcache_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0444 }, \ + .show = zcache_##_name##_show, \ + } + +#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \ + static ssize_t zcache_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return _func(buf); \ + } \ + static struct kobj_attribute zcache_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0444 }, \ + .show = zcache_##_name##_show, \ + } + +ZCACHE_SYSFS_RO(curr_obj_count_max); +ZCACHE_SYSFS_RO(curr_objnode_count_max); +ZCACHE_SYSFS_RO(flush_total); +ZCACHE_SYSFS_RO(flush_found); +ZCACHE_SYSFS_RO(flobj_total); +ZCACHE_SYSFS_RO(flobj_found); +ZCACHE_SYSFS_RO(failed_eph_puts); +ZCACHE_SYSFS_RO(failed_pers_puts); +ZCACHE_SYSFS_RO(zbud_curr_zbytes); +ZCACHE_SYSFS_RO(zbud_cumul_zpages); +ZCACHE_SYSFS_RO(zbud_cumul_zbytes); +ZCACHE_SYSFS_RO(zbud_buddied_count); +ZCACHE_SYSFS_RO(zbpg_unused_list_count); +ZCACHE_SYSFS_RO(evicted_raw_pages); +ZCACHE_SYSFS_RO(evicted_unbuddied_pages); +ZCACHE_SYSFS_RO(evicted_buddied_pages); +ZCACHE_SYSFS_RO(failed_get_free_pages); +ZCACHE_SYSFS_RO(failed_alloc); +ZCACHE_SYSFS_RO(put_to_flush); +ZCACHE_SYSFS_RO(aborted_preload); +ZCACHE_SYSFS_RO(aborted_shrink); +ZCACHE_SYSFS_RO(compress_poor); +ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages); +ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages); +ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count); +ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count); +ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts, + zbud_show_unbuddied_list_counts); +ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts, + zbud_show_cumul_chunk_counts); + +static struct attribute *zcache_attrs[] = { + &zcache_curr_obj_count_attr.attr, + &zcache_curr_obj_count_max_attr.attr, + &zcache_curr_objnode_count_attr.attr, + &zcache_curr_objnode_count_max_attr.attr, + &zcache_flush_total_attr.attr, + &zcache_flobj_total_attr.attr, + &zcache_flush_found_attr.attr, + &zcache_flobj_found_attr.attr, + &zcache_failed_eph_puts_attr.attr, + &zcache_failed_pers_puts_attr.attr, + &zcache_compress_poor_attr.attr, + &zcache_zbud_curr_raw_pages_attr.attr, + &zcache_zbud_curr_zpages_attr.attr, + &zcache_zbud_curr_zbytes_attr.attr, + &zcache_zbud_cumul_zpages_attr.attr, + &zcache_zbud_cumul_zbytes_attr.attr, + &zcache_zbud_buddied_count_attr.attr, + &zcache_zbpg_unused_list_count_attr.attr, + &zcache_evicted_raw_pages_attr.attr, + &zcache_evicted_unbuddied_pages_attr.attr, + &zcache_evicted_buddied_pages_attr.attr, + &zcache_failed_get_free_pages_attr.attr, + &zcache_failed_alloc_attr.attr, + &zcache_put_to_flush_attr.attr, + &zcache_aborted_preload_attr.attr, + &zcache_aborted_shrink_attr.attr, + &zcache_zbud_unbuddied_list_counts_attr.attr, + &zcache_zbud_cumul_chunk_counts_attr.attr, + NULL, +}; + +static struct attribute_group zcache_attr_group = { + .attrs = zcache_attrs, + .name = "zcache", +}; + +#endif /* CONFIG_SYSFS */ +/* + * When zcache is disabled ("frozen"), pools can be created and destroyed, + * but all puts (and thus all other operations that require memory allocation) + * must fail. If zcache is unfrozen, accepts puts, then frozen again, + * data consistency requires all puts while frozen to be converted into + * flushes. + */ +static bool zcache_freeze; + +/* + * zcache shrinker interface (only useful for ephemeral pages, so zbud only) + */ +static int shrink_zcache_memory(struct shrinker *shrink, + struct shrink_control *sc) +{ + int ret = -1; + int nr = sc->nr_to_scan; + gfp_t gfp_mask = sc->gfp_mask; + + if (nr >= 0) { + if (!(gfp_mask & __GFP_FS)) + /* does this case really need to be skipped? */ + goto out; + if (spin_trylock(&zcache_direct_reclaim_lock)) { + zbud_evict_pages(nr); + spin_unlock(&zcache_direct_reclaim_lock); + } else + zcache_aborted_shrink++; + } + ret = (int)atomic_read(&zcache_zbud_curr_raw_pages); +out: + return ret; +} + +static struct shrinker zcache_shrinker = { + .shrink = shrink_zcache_memory, + .seeks = DEFAULT_SEEKS, +}; + +/* + * zcache shims between cleancache/frontswap ops and tmem + */ + +static int zcache_put_page(int pool_id, struct tmem_oid *oidp, + uint32_t index, struct page *page) +{ + struct tmem_pool *pool; + int ret = -1; + + BUG_ON(!irqs_disabled()); + pool = zcache_get_pool_by_id(pool_id); + if (unlikely(pool == NULL)) + goto out; + if (!zcache_freeze && zcache_do_preload(pool) == 0) { + /* preload does preempt_disable on success */ + ret = tmem_put(pool, oidp, index, page); + if (ret < 0) { + if (is_ephemeral(pool)) + zcache_failed_eph_puts++; + else + zcache_failed_pers_puts++; + } + zcache_put_pool(pool); + preempt_enable_no_resched(); + } else { + zcache_put_to_flush++; + if (atomic_read(&pool->obj_count) > 0) + /* the put fails whether the flush succeeds or not */ + (void)tmem_flush_page(pool, oidp, index); + zcache_put_pool(pool); + } +out: + return ret; +} + +static int zcache_get_page(int pool_id, struct tmem_oid *oidp, + uint32_t index, struct page *page) +{ + struct tmem_pool *pool; + int ret = -1; + unsigned long flags; + + local_irq_save(flags); + pool = zcache_get_pool_by_id(pool_id); + if (likely(pool != NULL)) { + if (atomic_read(&pool->obj_count) > 0) + ret = tmem_get(pool, oidp, index, page); + zcache_put_pool(pool); + } + local_irq_restore(flags); + return ret; +} + +static int zcache_flush_page(int pool_id, struct tmem_oid *oidp, uint32_t index) +{ + struct tmem_pool *pool; + int ret = -1; + unsigned long flags; + + local_irq_save(flags); + zcache_flush_total++; + pool = zcache_get_pool_by_id(pool_id); + if (likely(pool != NULL)) { + if (atomic_read(&pool->obj_count) > 0) + ret = tmem_flush_page(pool, oidp, index); + zcache_put_pool(pool); + } + if (ret >= 0) + zcache_flush_found++; + local_irq_restore(flags); + return ret; +} + +static int zcache_flush_object(int pool_id, struct tmem_oid *oidp) +{ + struct tmem_pool *pool; + int ret = -1; + unsigned long flags; + + local_irq_save(flags); + zcache_flobj_total++; + pool = zcache_get_pool_by_id(pool_id); + if (likely(pool != NULL)) { + if (atomic_read(&pool->obj_count) > 0) + ret = tmem_flush_object(pool, oidp); + zcache_put_pool(pool); + } + if (ret >= 0) + zcache_flobj_found++; + local_irq_restore(flags); + return ret; +} + +static int zcache_destroy_pool(int pool_id) +{ + struct tmem_pool *pool = NULL; + int ret = -1; + + if (pool_id < 0) + goto out; + pool = zcache_client.tmem_pools[pool_id]; + if (pool == NULL) + goto out; + zcache_client.tmem_pools[pool_id] = NULL; + /* wait for pool activity on other cpus to quiesce */ + while (atomic_read(&pool->refcount) != 0) + ; + local_bh_disable(); + ret = tmem_destroy_pool(pool); + local_bh_enable(); + kfree(pool); + pr_info("zcache: destroyed pool id=%d\n", pool_id); +out: + return ret; +} + +static int zcache_new_pool(uint32_t flags) +{ + int poolid = -1; + struct tmem_pool *pool; + + pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL); + if (pool == NULL) { + pr_info("zcache: pool creation failed: out of memory\n"); + goto out; + } + + for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++) + if (zcache_client.tmem_pools[poolid] == NULL) + break; + if (poolid >= MAX_POOLS_PER_CLIENT) { + pr_info("zcache: pool creation failed: max exceeded\n"); + kfree(pool); + poolid = -1; + goto out; + } + atomic_set(&pool->refcount, 0); + pool->client = &zcache_client; + pool->pool_id = poolid; + tmem_new_pool(pool, flags); + zcache_client.tmem_pools[poolid] = pool; + pr_info("zcache: created %s tmem pool, id=%d\n", + flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral", + poolid); +out: + return poolid; +} + +/********** + * Two kernel functionalities currently can be layered on top of tmem. + * These are "cleancache" which is used as a second-chance cache for clean + * page cache pages; and "frontswap" which is used for swap pages + * to avoid writes to disk. A generic "shim" is provided here for each + * to translate in-kernel semantics to zcache semantics. + */ + +#ifdef CONFIG_CLEANCACHE +static void zcache_cleancache_put_page(int pool_id, + struct cleancache_filekey key, + pgoff_t index, struct page *page) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + + if (likely(ind == index)) + (void)zcache_put_page(pool_id, &oid, index, page); +} + +static int zcache_cleancache_get_page(int pool_id, + struct cleancache_filekey key, + pgoff_t index, struct page *page) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + int ret = -1; + + if (likely(ind == index)) + ret = zcache_get_page(pool_id, &oid, index, page); + return ret; +} + +static void zcache_cleancache_flush_page(int pool_id, + struct cleancache_filekey key, + pgoff_t index) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + + if (likely(ind == index)) + (void)zcache_flush_page(pool_id, &oid, ind); +} + +static void zcache_cleancache_flush_inode(int pool_id, + struct cleancache_filekey key) +{ + struct tmem_oid oid = *(struct tmem_oid *)&key; + + (void)zcache_flush_object(pool_id, &oid); +} + +static void zcache_cleancache_flush_fs(int pool_id) +{ + if (pool_id >= 0) + (void)zcache_destroy_pool(pool_id); +} + +static int zcache_cleancache_init_fs(size_t pagesize) +{ + BUG_ON(sizeof(struct cleancache_filekey) != + sizeof(struct tmem_oid)); + BUG_ON(pagesize != PAGE_SIZE); + return zcache_new_pool(0); +} + +static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize) +{ + /* shared pools are unsupported and map to private */ + BUG_ON(sizeof(struct cleancache_filekey) != + sizeof(struct tmem_oid)); + BUG_ON(pagesize != PAGE_SIZE); + return zcache_new_pool(0); +} + +static struct cleancache_ops zcache_cleancache_ops = { + .put_page = zcache_cleancache_put_page, + .get_page = zcache_cleancache_get_page, + .flush_page = zcache_cleancache_flush_page, + .flush_inode = zcache_cleancache_flush_inode, + .flush_fs = zcache_cleancache_flush_fs, + .init_shared_fs = zcache_cleancache_init_shared_fs, + .init_fs = zcache_cleancache_init_fs +}; + +struct cleancache_ops zcache_cleancache_register_ops(void) +{ + struct cleancache_ops old_ops = + cleancache_register_ops(&zcache_cleancache_ops); + + return old_ops; +} +#endif + +#ifdef CONFIG_FRONTSWAP +/* a single tmem poolid is used for all frontswap "types" (swapfiles) */ +static int zcache_frontswap_poolid = -1; + +/* + * Swizzling increases objects per swaptype, increasing tmem concurrency + * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS + */ +#define SWIZ_BITS 4 +#define SWIZ_MASK ((1 << SWIZ_BITS) - 1) +#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK)) +#define iswiz(_ind) (_ind >> SWIZ_BITS) + +static inline struct tmem_oid oswiz(unsigned type, u32 ind) +{ + struct tmem_oid oid = { .oid = { 0 } }; + oid.oid[0] = _oswiz(type, ind); + return oid; +} + +static int zcache_frontswap_put_page(unsigned type, pgoff_t offset, + struct page *page) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + struct tmem_oid oid = oswiz(type, ind); + int ret = -1; + unsigned long flags; + + BUG_ON(!PageLocked(page)); + if (likely(ind64 == ind)) { + local_irq_save(flags); + ret = zcache_put_page(zcache_frontswap_poolid, &oid, + iswiz(ind), page); + local_irq_restore(flags); + } + return ret; +} + +/* returns 0 if the page was successfully gotten from frontswap, -1 if + * was not present (should never happen!) */ +static int zcache_frontswap_get_page(unsigned type, pgoff_t offset, + struct page *page) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + struct tmem_oid oid = oswiz(type, ind); + int ret = -1; + + BUG_ON(!PageLocked(page)); + if (likely(ind64 == ind)) + ret = zcache_get_page(zcache_frontswap_poolid, &oid, + iswiz(ind), page); + return ret; +} + +/* flush a single page from frontswap */ +static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + struct tmem_oid oid = oswiz(type, ind); + + if (likely(ind64 == ind)) + (void)zcache_flush_page(zcache_frontswap_poolid, &oid, + iswiz(ind)); +} + +/* flush all pages from the passed swaptype */ +static void zcache_frontswap_flush_area(unsigned type) +{ + struct tmem_oid oid; + int ind; + + for (ind = SWIZ_MASK; ind >= 0; ind--) { + oid = oswiz(type, ind); + (void)zcache_flush_object(zcache_frontswap_poolid, &oid); + } +} + +static void zcache_frontswap_init(unsigned ignored) +{ + /* a single tmem poolid is used for all frontswap "types" (swapfiles) */ + if (zcache_frontswap_poolid < 0) + zcache_frontswap_poolid = zcache_new_pool(TMEM_POOL_PERSIST); +} + +static struct frontswap_ops zcache_frontswap_ops = { + .put_page = zcache_frontswap_put_page, + .get_page = zcache_frontswap_get_page, + .flush_page = zcache_frontswap_flush_page, + .flush_area = zcache_frontswap_flush_area, + .init = zcache_frontswap_init +}; + +struct frontswap_ops zcache_frontswap_register_ops(void) +{ + struct frontswap_ops old_ops = + frontswap_register_ops(&zcache_frontswap_ops); + + return old_ops; +} +#endif + +/* + * zcache initialization + * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR + * NOTHING HAPPENS! + */ + +static int zcache_enabled; + +static int __init enable_zcache(char *s) +{ + zcache_enabled = 1; + return 1; +} +__setup("zcache", enable_zcache); + +/* allow independent dynamic disabling of cleancache and frontswap */ + +static int use_cleancache = 1; + +static int __init no_cleancache(char *s) +{ + use_cleancache = 0; + return 1; +} + +__setup("nocleancache", no_cleancache); + +static int use_frontswap = 1; + +static int __init no_frontswap(char *s) +{ + use_frontswap = 0; + return 1; +} + +__setup("nofrontswap", no_frontswap); + +static int __init zcache_init(void) +{ +#ifdef CONFIG_SYSFS + int ret = 0; + + ret = sysfs_create_group(mm_kobj, &zcache_attr_group); + if (ret) { + pr_err("zcache: can't create sysfs\n"); + goto out; + } +#endif /* CONFIG_SYSFS */ +#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP) + if (zcache_enabled) { + unsigned int cpu; + + tmem_register_hostops(&zcache_hostops); + tmem_register_pamops(&zcache_pamops); + ret = register_cpu_notifier(&zcache_cpu_notifier_block); + if (ret) { + pr_err("zcache: can't register cpu notifier\n"); + goto out; + } + for_each_online_cpu(cpu) { + void *pcpu = (void *)(long)cpu; + zcache_cpu_notifier(&zcache_cpu_notifier_block, + CPU_UP_PREPARE, pcpu); + } + } + zcache_objnode_cache = kmem_cache_create("zcache_objnode", + sizeof(struct tmem_objnode), 0, 0, NULL); + zcache_obj_cache = kmem_cache_create("zcache_obj", + sizeof(struct tmem_obj), 0, 0, NULL); +#endif +#ifdef CONFIG_CLEANCACHE + if (zcache_enabled && use_cleancache) { + struct cleancache_ops old_ops; + + zbud_init(); + register_shrinker(&zcache_shrinker); + old_ops = zcache_cleancache_register_ops(); + pr_info("zcache: cleancache enabled using kernel " + "transcendent memory and compression buddies\n"); + if (old_ops.init_fs != NULL) + pr_warning("zcache: cleancache_ops overridden"); + } +#endif +#ifdef CONFIG_FRONTSWAP + if (zcache_enabled && use_frontswap) { + struct frontswap_ops old_ops; + + zcache_client.xvpool = xv_create_pool(); + if (zcache_client.xvpool == NULL) { + pr_err("zcache: can't create xvpool\n"); + goto out; + } + old_ops = zcache_frontswap_register_ops(); + pr_info("zcache: frontswap enabled using kernel " + "transcendent memory and xvmalloc\n"); + if (old_ops.init != NULL) + pr_warning("ktmem: frontswap_ops overridden"); + } +#endif +out: + return ret; +} + +module_init(zcache_init)